Yup, I understand where you are coming from. You can look at someone's job history if they are not too young to have a "track record" (job hopping would be a counter-indicator while promotions would be a positive).

I was lucky enough to have been a mentor for a pre-accelerator start-up last year alongside someone who proved over a few months to be an effective marketeer and manager. That start-up foundered for all sorts of reasons but the marketing person is now a key part of the team for my current start-up.

I suppose I am saying - the only way to find out is to give them a try. If someone is genuinely enthusiastic about the product and has some positive ideas and the cultural fit feels right then why not?