ID Chip Placement

So I was watching This Video on BBC news about a few students in America trialling ID chips by using them in their hands to login to their computers and I think they have them in completely the wrong part of their bodies.

See in their hands they wait for the login screen to appear then they put their hand on a pad. The chip is read and they are logged on, but if they had the chip implanted in their ass instead then the system would work much better. Then they would just have to sitdown infront of the computer and when the login screen appeared, the pad in the seat of the chair would read the chip in their ass, removing the need for all that hand waving rubbish. Plus the system could automatically lock itself when the user stands up, thus greatly improving security too.