This isn't new. My au pair tried to sign up to be an Uber driver 5 years ago, using my car. I found out after we rematched and she returned the phone I paid for without logging out of her email account. She didn't succeed because she didn't have a license here (she completely failed the driving evaluation I paid for, so it is kind of amazing that she even had the balls to try signing up as an Uber driver). I added a prohibition on doing this to my au pair handbook (but also have stopped using au pairs because they are unreliable in normal times, but certainly can't be trusted to keep my high risk family safe during COVID).
She also applied for nanny jobs through nanny agencies, which is the ONE reason an au pair agency will actually kick an au pair out of the program (I forwarded those emails to the area director). They can do anything they want to host families and kids (she almost KILLED the host kid in her next family, who had a food allergy), but God forbid they turn out to be disloyal to the agency, THEN they get sent home!