He knows the dangers of a cell phone (or a shopping card, or even non-free
software), but he also knows the benefits, and believes that the dangers
outweigh the benefits. However, using someone else's cell phone allows him
the benefits without the drawbacks. It's a cute hack, really.
It's pragmatism more than anything else, I think. While he refuses to use or
own any of those things, he realizes that not everyone will go along with
him, so he'll take advantage of another person's cell phone (or whatever)
instead of refusing it on pure ideological ground.
However, his life style isn't dependent on other people providing him with
their cell phone. It's a convenience. I imagine most places he goes have land
phones available for use if he needs a phone and no one in his vicinity can
provide him one.
