I know some here (LTG, Vid?) will remember when Midway introduced Ms. Pac Man. It instantly made the original Pac Man, which was making big money for ops, look like a B&W teevee. It used the same main logic board with different program chips (which all ops had figured out how to duplicate by then, copyright notices be damned) and an expansion board that that had a few new program chips with another seeming odd chip with "MMI" inked on. There was also one of these on the main logic board's memory circuit as well, IIRC. All of us ops thought that was a chip made for Midway Manufacturing Inc./MMI even though the company name was Midway Manufacturing Company-A Bally Company.
Eventually some ops, including the one I worked for, realized MMI was Monolithic Memory Inc. and the IC's were Programmable Logic Arrays (PAL's) which programming devices (truly a "burner" if there ever was one) were difficult to get. Some of us ops did figure it out quickly (a graduate EE friend of mine helped us with that) and the CONversion to Ms. Pac Man began without Bally Midway or Namco making a penny.
For an amusement game manufacturer, they were not very amused. US Marshalls began CONfiscating machines on location as well as busting the doors down at operator offices/warehouses. There were huge fines and a few went to jail over this. The op I worked for smartly set up a remote location to perform the CONversions and store/rotate/ship the machines from. That place was never discovered. We did have a shitload of the machines CONfiscated. I had to give a deposition or three myself. Fortunately, nothing happened to me. Actually, a positive came from it in that Bally Midwest, the distributing arm of Bally in the Detroit area hired me. Whodafcukknew????
Nintendo was even less amused over the "Crazy Kong" and "Monkey Kong" knock-offs of their Donkey Kong machines.
The ops who did this are long-gone so no need to report this post to Eliott Ness.