The only people to complain would be people with something to hide.

I don't care if the goverment knows what I'm doing and buying etc, like Jim said they do it anyway this would just me an easier way of doing it, and would perhaps erradicate the need for passports and having to have loads of different types of ID card on you constantly.

The ultimate would just be to microchip everyone so their movements can be tracked too, it could help solve a lot of crime, just check where someone was at a certain time and track them.