The issuing airline doesn't have to sue. it can and will just charge the same card used to buy the ticket. And, as stated above, if the passenger wants to sue to try to recover the money, s/he will not be in small claims court, so s/he will be coming up with money for a lawyer . . . who will have to convince the court that the rules either don't say what they clearly do, or that they don't apply to this passenger.

But by all means, stick to your guns! And let us know how it turns out!!