I guess it depends on what information they actually carry on them. For instance, the ID cards carried by the French (and the photocard part of the new UK driving licences) have home addresses on them which I think is a dangerous idea, especially for women. Plus, it's like everything else - the law abiding amongst us will get ID cards and the criminals will just get fakes. I think it's just another step closer to the "big brother" society George Orwell invisioned in 1984.
