Good intentions, but maybe not the best idea. Although they have come down in price, kids are not always exactly responsible, and it would give some one that much more reason to break into your store. If you live in a nice area, have good security, and can secure the PS3 so it has a minimal chance of getting broken, and can afford it, sure why not. It might give you or your employees something to do during down time also.
I think it would be a great idea,the town that I live in at the local barber shop has a ps2 nintendo 64.Which really helps when waiting your turn to have your hair cut.No one hangs afterwords to finish the games there were playing,Kids really love it,I know my do.
just like you said is good and bad ...you will get a lot off people hanging around because they will want to finish the game they start it and other people will watch them play..i wouldn t do it.
I would not do it. It may attract the wrong kind of people. Who will hang around you shop driving a way paying customers.