Quoted from RacerRik:I am just concerned about what bad might come from leaving the coin door interlock for memory protect disabled.
Not much. The coin door interlock disable was a holdover from the WMS 3-7 era 9 (& possibly earlier), when WMS was using reallllllllly crappy cabinet bottoms. What would happen is people would either punch out the speaker (when it was forward mounted) or drill/cut the bottom of the cabinet to get the coin box. After that, they'd play with the buttons to set the game on free play and/or something stupid like 10 credits / coin drop. With the coin door protection feature, if the coin door was closed then you literally can't write ANYTHING to the section of RAM that stores settings.
You can see remnants of this on some old machines, where they have a steel plate on the underside of the cabinet. Didn't fix the puch-the-speaker-out problem, though that slowly migrated to the back of the cabinet.
It technically also protects the RAM against an accidental write while powering up/down. But I think that's a technical possibility rather than a likelyhood. I have a few games where I permanently shorted the memory protect, and many years later have never had a problem with them.