Is she deemed as a contractor? Does the company file her taxes? Being paid or not paid based on outcome is usually somwthing i see on contracts which companies force people to become to skirt labour laws and make payment based on ourcome instead of hours.

This changes the answer for you, because the reason they do this is it puts the onus on you to make everyrhibg perfect becayse they are paying for a piece of work.

There are indeed laws that punish companies that do this however but is based on location and all that (fwiw im not a lawyer)