To move things onwards slowly but swiftly, an article on tagging passengers around airports caught my eye. In particular, there seems to be a trial going ahead despite readily-foreseeable weaknesses:
Colin Brooks, Optag co-ordinator, said the trial would determine if the tags would be feasible in the light of obvious problems, such as the possibility that people might ditch their tags to avoid detection, or swap them with another person.
The obvious way to solve this is to implant tags upon entry (in fact, don't some trendy bars (run by Kevin Warwick?) do this now? :-/ ), or maybe just some super-strong glue will do the trick. Either that or make sure they explode if removed within designated zones...
Also note that the first listed reasoning behind it is "improving airport efficiency". Contemplate that for a moment, and remember that, by nature, humans are generally quite "inefficient" anyway.
It's been a couple of months away, but we still need to ask what we really want our technology to do for us, or to us.