Hehe, the funny thing is Dariusz didn't even bring up the console thing, GameDork did.
What makes it a bad idea is there is no need for it. What's the difference if you put in the coin before or after you select the game you want to play to how "authentic" it is? having something like that isn't authentic at all except for the playchoice type systems which is 90s

If you put the credit in before or after you still would have to put the credit in so how would that change anything?
The other issue is getting that credit sent to mame, it can be done but not easily. What would have to be done is the FE would have to wait for mame to start then queue up the credits by sending the keyboard code you have selected as coin. So you couldn't really hit any other keyy while the FE is doing the key presses. It could cause a nightmare, at least a lost of credits.
What the others have said. It's a potential legal nightmare. I actually used it as an example a while back of what you could do via the new controller files... but it was more of a "wow this new format is cool" thing. I would never actually do it because what you have done then is setup a free way for pirates to make a pay "mame" machine.
HC, are you talking about putting credits in the cfg xml files. That only works for a couple of games. Most that I tried it doesn't work anyway.