You honestly think Uber would risk their customer's credentials to shut out a competitor they are already trouncing by most accounts? I would consider the risks of using customer's credentials in such a careless and ridiculous way many magnitudes higher than the potential rewards. It's much safer to buy burner phones and assume fake identities. Sorry, it just doesn't make sense without some evidence to back up it up.

Credentials? They would just need a username, unless I'm mistaken?

> the risks of using customer's credentials in such a careless and ridiculous way many magnitudes higher than the potential rewards

Are you sure? What are the risks of parking a username? I doubt it's illegal and I bet they could obfuscate the traffic well enough to make it very difficult to prove to a court that they were the ones doing it. The only downside seems to be a bit of slightly negative PR (i.e. the assumptions of those who jump to conclusions) when Lyft detects the widespread parking.

Meanwhile, the upside is the expected value of their most profitable customers times the probability that they will switch to Uber+Lyft or 100%Lyft.

Low risk, large upside... I don't think this is as bad a business proposition as you make it sound like.

Slightly negative PR for having the monopoly in the long term? I'd take the negative PR any day.

Jail time for fraud?

Have you seen people go to jail for parking domain names? We aren't talking about stealing credit card numbers here.