Is it unreasonable for console manufacturers to take measures to prevent used game sales?

It's not confirmed as yet, but it's entirely possible that both Sony and Microsoft could take measures to prevent used game sales with their new consoles. The prospect of this is obviously abhorrent to the big game retailers because they make a killing off used games sales and I've heard many claim that to take such measures would be anti-consumer. However, would it really be such an unreasonable move?Used game sales arguably have a greater detrimental effect on the games industry than piracy because while you can never prove that a pirated game represents a lost sale, it is a fact that used games (which publishers/devs never see a cut of) are often sold in place of brand new copies at retailers such as GameStop (they might knock five dollars off the full price for a game that is in pristine condition, for instance). So given that used game sales represent millions of dollars in net loss for the games industry, we surely can't blame MS and Sony for considering this sort of thing, or can we? Where do you stand on this issue?