Would def have to use a rating. I think if a person- rider or driver- was worried about that then they wouldn't want to use something like a protocol based ride share and would instead stick to uber.

But I do think there is a certain consumer/worker out there who would utilize it to keep more of the value generated by their labor. Riders would pay less and drivers would earn more without the middle man. Uber could not compete and stay solvent as a company.

Eventually it will get so popular no one else will want to use another system.