It's an interesting concept, the degree of consent. There's absolute consent, saying that the person has to absolutely consent to every single interaction that is going to happen, and that's very impractical, all the way to the fact that....
I don't know whether you saw that in Toronto a council person suggested that all cellphones' FM frequency ability should be turned on so that in case there's any emergency, they can get to every single cellphone with a broadcast. You can argue that this is a socially responsible consent. Sure it is, because no matter where you are in the area and where they need to find you, it doesn't matter; it's for the benefit of the social good, because there might be an emergency such that you need to be found—that type of consent.
Also, there's consent whereby you simply contract with a cellular service provider to use their service, and because of that—they have to know your whereabouts, obviously—they're able to build a better network.
It's the degree of consent, then, that's the issue.