Microsoft has yet to make its full official announcement about how their trade-in and used game policy is going to work and there has been a lot of commotion surround the "activation fee" that will be active on used games.
Many users have been concerned that used games will require a fee to play, which was suspected to be the full price of the game, but could even have been a system of charges similar to that of the EA online pass scheme, unfortunately Microsoft has still to release details on price, but it's more than likely to be fairly dynamic, much like the retail value or anything else, or perhaps even a percentage based system.
If retailers are to foot the bill it could mean that lending a game to a friend won't in fact cost you anything and that retailers may just have to pay to re-licence the title to a new user.
It is rumoured that Microsoft hasn't even figured out the fee yet, but then we have problems with how much does the fee decrease over time for older games, will used games cost more, will new games cost more and many other concerns.
Microsoft has asked for patience and they're right to do so, people have been quick to rage about all this and I can't figure out why people are jumping to wild conclusions about this system when nothing has been set in stone. My advice is that if you hate what Microsoft is doing, don't buy their games, contact them with a structured message, be polite and you'll be heard, because no one cares if all you’re going to do is troll. Ultimately though, we will know a lot more at E3 and with a console release later this year, we won't have to wait long to find out the finer details.