They can take you to court for breach of contract, and if (IANAL) the subscription contract is found to be legit, you have to pay + fees.
For that there would have to be a much more transparent sign up process and actual delivery. Non-performance is not a good basis to start a law suit, especially if you're on the non-performing side.
Most large merchants have risk mitigation strategies that attempt to detect this before a charge gets processed and goods are shipped but that's a less-than-perfect mechanism.
Second: Are you a lawyer? Is that the guaranteed outcome of such cases? Will it really carry no weight that they can (probably) substantiate their claim that you checked the box with a technically sound argument that their website actually works? A manual release test plan, unit tests, cucumber scripts?
That one, single checkbox, and the fact that you have to manually check it, is the legality upon which the entire business hinges. Especially if they're a little shady, they'd be sure to have their stuff in order around this.
I'm not a lawyer, but I am a programmer. I would never swear that my software works so correctly that I will use the actions of the application as proof that a user did check a box. If he claims he didn't, well, he just may be right. I've seen enough weird things happen not to trust any software to behave correctly all the time.
Now my technical reasons may not be relevant for a judge, but I doubt judges are very trustworthy of technology (they should have heard plenty of cases where technology failed and they will be users of all kinds of awful consumer technology, that sometimes, suddenly fails for no clear reason) and won't think favorably about a company with these kinds of practices. Perhaps I'm naive, but those things combined will lead a judge to believe you over the company.
That one, single checkbox, and the fact that you have to
manually check it, is the legality upon which the entire