If everything is identical about them (case was in same condition, discs were scratch-free, etc), I wouldn't care that much. Heck, I wouldn't be surprised if this happened with Super Smash Bros parties friends and I had a couple of times. I do remember leaving one of those with someone else's Gamecube controller somehow (which meant someone else threw it in my bag). The only physical copy of something I probably really have any attachment to is my copy of FFVIII. It is possible I'd get sad at the thought of somehow going home with a copy of that game that wasn't my own.