You could investigate the people in charge of the company and their backers. If you think they have more to gain by draining a small number of peoples bank accounts than they have to lose by committing a federal fraud crime then don't use them. Obviously any evaluation would also depend on the credibility of the information presented on the website about those individuals.

I don't make any purchases with my debit card, so I would only link my credit card, which has pretty solid fraud protection. I'd probably be more way about cash accounts.