Ethical question

[dapearl]

Hoi there! I've got an ethical question here for you. Now i've BOUGHT ALL my games ... however, I've now been introduced to the ability to back-up my games. Actually I've only had one success (Soul Calibur) and 2 failures (NCAA2004 & Splashdown).
My question to you guys that might know ... if I have actually bought the games that I own ... and I succeed in making a back-up. Would it be illegal for me to sell back the original to EB (NOT full price) and get a lil discount on buying another new game full price @ gamestop or EB?
Or another possible twist ... if I could ever make myself wait for the price to drop on a used one like say ... SSX 3 (good luck on that! i don't think I could wait for a used one to come back) and then sold my original game back and used credit for another game while keeping my back-up ... would that be considered illegal ... even though I DO pay full price for my game?
What do you guys think? I'd really like to know. Preferably from a definitive source instead of just opinions

Dapearl