I just got off the phone w a VZW rep for an unrelated issue. While I had him on the phone, I asked him this question. He suggested to ensure I avoided charges using this, I should call and make sure the hotbot feature is cancelled (?!) At the end of the trial period.
If he's right (and he may not be) this would be a horrible hidden charge! As a side note, the reason I called in the first place was to cancel a charge that my son incurred while playing the "free" pre-installed game (the golf one). Ridiculous. He didn't even hit the first ball before it said something would show up on my bill. He brought it to me (after playing with it for 60 seconds) and the message was on the screen! So much for a free game...I'm guessing I can't even reinstall it.