And it makes good business sense besides. They can let the guy off and eat the probably less than a hundred or so bandwidth this guy actually cost them due to their upstream providers, get a good writeup and look better as a result,
..or kill his account, take him to collections, etc, etc, etc, (which would probably cost them more than $1K anyways), and lose a customer and get a PR black eye while they're at it.
So yeah, it would be a jerk move, and a pretty dumb one at that.