As I recall, the basic differences between employee and contractor are whether the employer can dictate time, place, and manner. The problem for gig "contractors" is that they're in a much tougher spot on exercising their rights, since not many people who can afford a lawyer deliver food. And they aren't exactly in short supply, so if Uber oversteps and individual "contractors" try to push back, they'll just be fired. Which gets back to the lawyer issue.