I had this happen on two of my games, thought I was loosing my mind. It happened again a week later so I changed everything back.... and then one more time three weeks after that. All three times the games were set on easy and the tilt was all the way down or off.

After changing the locks it stopped happening. No money was missing from what I could tell, Just settings and tilt.

Had a place ten minutes from me get taken for almost 2k on their "grey area games". They said they were changing locks and the bartender and regulars didn't think anything of it. As far as I know, they never got caught.

The only problem with tubular locks is they are insanely easy to pick... guess it's the same thing with most wafer locks.
Done it myself dozens of times.
I was actually considering going with medeco, but holy they crap are they expensive.

Chances of people actually buying a pick to open a pinball machine are pretty damn slim though. Other items maybe.
Seems like they are just as likely to use a crow bar or steal the whole machine.

I know you can find most locks, like medeco and other better brands with security pins. Most, including myself just go with the cheaper alternative... Guess it's kind of like insurance. you know it's probably a good idea, but the upfront cost makes it less appealing. I'm probably going to bite the bullet sooner then later.

After you've seen, heard and experienced enough theft it starts to make you paranoid.