Capitalism is based on the idea that both sides agree to exchange what is promised, not merely something someone else thinks is close enough.
You can't offer to sell "Lamborghini" and deliver a kit car with a Lamborghini shell and a 1985 K car motor under the hood.
If they do not want to be legally held responsible for what the services they do, then the answer is simple - do it for free, with disclaimers about not promissing anything.
Because the second they charge money for their services, they become legally responsible to actually fulfilling what they offer, rather than the mistake. And yes, the penalties correspond to the costs and pain incurred, rather than merely being limited to the amount they charged.