This isn't actually being thought about, it's just Wal-Mart saying they might do something so people will talk about them and give them free advertising. There are so many things that could go wrong with this. Privacy of both parties, liability if something is delivered broken etc. The biggest I think is if someone that is delivering a package gets in a car accident, there are a bunch of liabilities there too. Who pays for it? Of course, knowing Wal-Mart (and all big companies), if they were to implement something like this, they would require any delivery drivers to sign a liability release.