Uber doesn't 'employ' their drivers. They are contractors. AFAIK an illegal can get a TIN, which combined with their home country's identity documents would be sufficient to legally complete the paperwork to pay out the contract [note this is not legal advice.]

You'll notice this pattern lots of places. Look around in employment ads for construction gigs in lots of cities and they'll be looking for 'contract' teams which we all know likely means some illegals who setup a genuine LLC or get a TIN or whatever; there's no requirement to verify legal employment when paying out a contract AFAIK.

In California it might but I was thinking more in generalities of all the other startups we have had when Uber came to be.

For example, GigWalk.