I don't know about the US, but here in Germany you can't put that kind of stuff into your terms and conditions.
Well, you could, but those terms would be ineffective. Of course, this doesn't help if they succeed to intimidate the victim. But if the victim doesn't pay, there's nothing the scammer can do, because this case would never succeed in court.
Having said that, it might help if the victim complains to the police. Depending on how serious customer protection is taken in the US, this business might be more than merely "unethical".
Not only ineffective, but its planned to make this deceipt downright illegal. You have to state all of the costs in clearly readable text on the signup page itself and change the button to indicate that you are signing up with recurring costs.