How exactly did they rip you off 3 times? Did they steal your games, store credit, or money from you outright? If they've managed to get over on you a total of 3 times now, WHY are you still going back?!
Haven't you heard of "Three strikes and you're out!" or the phrase that offers less chances such as "Fool me once, shame on you. Fool me twice, shame on me"?
I am genuinely curious how they could have ripped you off more than once. I can understand if you traded in a 3ft tall stack of games and they missed one. I can also understand if they lost a store credit back when it was paper based. I can even understand someone accidentally short changing you at the end of a transaction because they got distracted or transposed some numbers and gave you back .23¢ instead of .32¢. All three of those examples are honest mistakes that could be easily remedied if one was astute and on the ball.
Could it be then, and I'm speculating here, that the scenario you're referring to where they would have allegedly ripped you stems from 3 separate occasions where you took in piles of games/accessories to trade, they pitched you a lowball $XX amount, and you expected a much higher number than the one quoted? If that's the case and you took them up on their offer, then the only person who ripped you off was you. Again, I'm merely speculating, but it's been my experience from years of working behind the counter as well as seeing a bajillion posts online where people would say they were ripped off, after their initial put downs there would usually be some yammering diatribe about their lowball trade in amounts that followed.
Oh you slick fox you! How clever!
If I had a nickel for every time someone did this "trick" I would be a very, VERY rich man. I hate to sound like I'm coming off as condescending but perhaps you should be taking better care of your games in the first place to where they won't get all scratched up and thus necessitate the need to pull off this "trick"? Now if you're finding games in the wild that are a little rough looking but you netted it for a great price, I'd be a little more understanding to your switch-a-roo shenanigans. Still though, I've been in that situation myself and I've passed on games that were too rough as I figured it's just one copy and eventually I'll find a more better looking copy elsewhere for around the same price.
Doing the disc/case/book/insert switch-a-roo qualifies as a scam now?
Criminy, if that's the case, I can only imagine the magnitude and labeling pyramid structuring and Ponzi schemes merit then. I realize the disc thing is a little off the cuff but I've NEVER had a problem asking for an instruction book from a case if it was one I needed (which is super stupid rare as I'm very picky about my purchases to begin with). I've done it at stores where I didn't know any of the employees. I always figured the worst they could say to me was no. Even if they did say no, and you did the swap/return, I can't really see myself dressing that scenario up and calling it a scam.
Incidentally, your openness about you say you scam them is a minor concern. I hope your field of employment doesn't include that of a Realtor, financial adviser, or commission based salesperson.
Rape? Seriously? I'm sorry, but that's an incredibly poor choice of words on your part. Having bad experiences with a place that you feel has done you wrong more than once (and yet you still go back) compares not at all, even an inkling, to the incident of rape. -100,000 Internets for you good sir.
Even so, and I'm not even sure how this escapes you, as the consumer YOU have the ultimate power over any retailer. It's your choice whether or not you do business with them. At any point in time where you feel like you're not getting your due, YOU have the ability to stop the deal dead in it's tracks. This isn't like a mortgage or a auto loan where once you've signed on the dotted line you're fighting up uphill legal battle to renege on the contract. This is WAY more simple.
The fact that it needs to be pointed out and the fact that it appears your stance is "Well they're screwing me over, turnabout is fair play" scares me that there are people like you out there. I guess it's too much work and effort to take a little responsibility and be more meticulous about your purchases up front, take care of your property so it remains scratch free, and saying "Fuck NO" to a retailers lowball offer by selling your items on your own via the internet or garage sales for what they're truly worth. I mean come on...we know nothing is YOUR fault right?