Pretty sure traditional taxi/sedan services have records and get in a lot of trouble if they are falsified. I guess it’s possible that there is a massive spree of under the table lying going on, but I imagine companies can catch on to that. Even moonlighting is difficult because the vehicle is not a personal vehicle. And the local taxis here have tracking and apps that are very close to Uber’s even if they are not as attractive. I know the name and cab number I get a ride with using he app.
Even so, I doubt that it is more or less likely than either. They both would attract the same kind of predator interested in using it that way, and even with huge bold red scarlet letters on their background check they do slip through the cracks one way or another.