App that automatically cancels subscriptions after free trial, launches in UK

I feel like this solves a problem which shouldn't really exist - In a perfect world a free trial really should be free and should allow you a choice afterwards to either cancel or continue.

That said I think the concept of using essentially fake bank accounts seems somewhat legally dubious. Surely when you start the subscription you are entering a contract with the company, so when the company is unable to retrieve any money I would assume the individual would be the one liable to legal action? Would make pretty bad press though so I can't imagine any company actually doing this.