'My Key Opened My Neighbor's Door!?'

This is a strange news story, for sure, but the explanation might be more common than you'd expect. Enjoy! 👍😁👍

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[AuthenticUnicorn]

10:52: talks about handy door straps that can be used on virtually any deadbolt! They're not in stock at the moment, but you can sign up to be notified when they're back here:

[matt]

alternate and much funnier explanation: the builder didn't know what a builder's key is for and just handed "the keys to the house" to the residents as they moved in

[rolon]

When I was young, I once tried to withdraw money from a cash machine at the railway station at night while drunk. Unfortunately, a blind was already down at the time and access was blocked. In my drunken frustration, I tried my front door key.
It worked.
So I was able to withdraw money, and I've been interested in locks ever since.

[aarocka]

This is why houses should look somewhat unique instead of just the same copy and paste suburb. When I lived in Texas, somebody was shot through the door because he was banging on what he thought was his friends door to let him in, but he was actually at the house next door.

[MarkRose]

At a former workplace, the interior doors used house keys. One day I was having a little trouble with the lock in the door, but eventually got it open. Inexpensive door knobs can sometimes be that way. Then I realized I had used my house key. As it turned out my house key would open many other doors, being not far off from a skeleton key for the building.

[yt]

I’ve not read the other comments, so I’m not sure what others have said. Once the homes are under construction, and they can be locked up, it’s not unusual to have keyed alike locks on the doors so they can give a key to a subcontractor. A A plumber or drywall installer can go into the house without having a representative on the spot to let them in.

[jhbange]

Happens a LOT, even if they DIDN'T inadvertently buy keyed alike locksets. Over the course of 30 years as a locksmith, I have on MULTIPLE occasions gone to key a lock on an apartment or house, grabbed a key set from the "bucket of factory key sets" all locksmiths end up having, and been irritated to discover that the dwelling was already keyed to that key set! Off the shelf Schlage locks have a theoretical keyspace of 10^5 (10 depths, 5 cuts) for 100, 000 possibilities, but from the factory locks up until recently were pinned only with keys cut with depths 3-9 because the mechanical "random key cutter" Schlage used couldn't discern when two adjacent cuts were too far apart in depth such that the deep cut's sides would obliterate the shallow cut's flat. So their solution was to have the machine cut only 3 or deeper, so the Maximum Adjacent Cut Specification--- for Schlage with a 47 degree cutter it's 7--- is never violated (from 3 to 9, the difference is only 6). TL;DR on all that locksmith jargon, the keyspace for a Schlage factory cut key was for many decades only 7^5, which is 16807 possible keys. And for original Kwikset (and for a lot of Kwikset knockoffs) it's even worse. 6 depths, 5 spaces is 6^5, which is only 7776 possible keys. And between Kwikset and Schlage (and knockoffs thereof) that's like 98% of as-built residential door locks out there.

You can't 100% trust that your typical door lock from the factory isn't keyed the same as someone else nearby. Best approach is to either rekey to a 6-pin key (if possible) or replace the cylinder with something that's not KW1 or Schlage C keyway. If you can't, definitely get a second means of securing your door from the inside like DO says.

[Tom_Losh]

Common biting on random locks seems to happen much more often than most people realize. At a car "meet and greet" gathering a few years ago one of the attendees accidentally locked his keys in his car. Since they were all the same make of car, he had folks near him try their keys in his door to see if any were close enough to wiggle 'em open. I think it was something like the sixth key was an exact match ...

[timbober]

Retired semi driver here, always been interested in locks. I accidentally locked myself out of my truck one night, I called my dispatcher and he told me to break a side window. I felt pretty stupid, I tried to sneak in a coat hanger with no luck. I did have my personal keys in my pocket. I found a key that fit and giggled it around and got an open. I tried the same method on a number of the tractors (all keyed alike). I could get into most of them. Lucky no disciplinary letters, the mechanics in the shop were impressed.

[eggman]

This is why when you buy or build a house, NEVER leave existing locks in place unless you get them re-keyed by a locksmith, and NEVER let a contractor pick out and buy your locks for you. ALWAYS provide your own. Also have an alarm system in addition. Locks should just be a single layer of a multi-layered approach.

[spudd]

My dad had a classic Mini as a teen. Hi key opened most other Minis he tried it on. This relationship was one way, the keys for Minis his could open would not open his. It is important to note that his key also *started* those other cars.

[EyeMWing]

Your story about the master wafered medecos raises an interesting question. I was always told that stacks of multiple small master wafers, in addition to being wildly insecure, are also very unreliable because they will tend to flip up and jam at the shear line. I’d have thought that doing that for an extended period at building scale would result in enough messed up locks for a real locksmith to get called in and notice.

Might be interesting to shove a bunch of wafers in a lock and see what it actually takes to cause a jam.

[matthewellisor]

Recently visited a friend who just closed on a cookie-cutter house and offered to change their locks to a set of Primus I had around just for sport. What was installed was clearly just off the shelf and probably from the nearest big box.
Figured out that their nearest 2 neighbors (probably others too) had identical bitting so I rekeyed each of theirs too while they were finishing the brisket. A few minutes of playing with pins and nibbling keys for a nice meal and new friends is a good Saturday!

In other news, local PD and SD have finally changed out the remaining 1284X but I still keep one in my wallet. Don't know if it was from (with permission) putting a baggie with a can of Coke in Capt.'s trunk but who could say?

I need to go save slides from your "This key is..." presentation.

[TheWolf]

old soviet story, the burglar just bought a big bundle of different keys and simply matched them during his burglaries. soviets manufactured no more than 35 different key combinations of livks at the time.

[JoeHamelin]

My neighborhood in Yakima, built in the mid 60s, had a master key for all the homes on the block for the construction workers to use. They never changed them out when they were sold. The master was mostly a zero cut at that. One of our neighbors was one of the house builders and showed us.

[BurningMonkey]

I worked as the assistant field superintendent for a major home builder
all of our locks where keyed alike until the house got bought
then the locks would get changed [sometimes, maybe]
working that job really opened my eyes to how insecure houses really are

[iblackfeathers]

imagine all those keyed alike police squad cars and taxis in the day.

[vidakk]

Many moons ago, a friend and I came to our small local boardgames club. We left the key with another friend who was being very late, so being bored, I tried my apartment key and, lo and behold, it worked perfectly.
Few years forward, I moved, and then discovered that a key to that apartment opened the offices of a student org I was a board member at the time in the Uni building. The lock was old and crusty, so it even worked better than the original key.
None of these locks were master-keyed. Both were 5-pin euro cylinders.

[artstrutzenberg]

Million dollar question: at 1:02 the reporter has his keys clearly there enough fidelity/input/feedback that somebody could replicate that key?

[UnlikelyToRemember]

In HS (many years ago) my Mercury's key also fit a friend's Ford -- I guess there were only about 2000 possible keys back then