[tfehring]

Edit: On second thought this is probably a bad idea, but I'm leaving my original comment below for posterity.

Probably easiest to generate a virtual card number with a spend limit, off the top of my head I know Capital One offers this, Apple will also generate virtual card numbers though I don't know if you can set a spend limit on them.

[pxx]

This just stops them from easily charging you. It doesn't change your liability.

[tfehring]

Yeah good point, I was thinking they'd cut your service off but on second thought that's probably not the case.