> Why would you side with that?

Because the letter of the contract and law is more important than reasonableness or ethics.

If the law in your jurisdiction requires more than payment of actual damages in this sort of situation, then I would argue that your law is broken. Clearly those damages can not exceed the full cost of the original plan plus any actual costs of dealing with the early transfer, so a bill for 100+ bucks is just a shakedown, pure and simple.

Not quite true. If the contract asked for a pound of the customer's flesh I'm certain it'd get thrown out in court.