It had been a tumultuous weekend for UberX, the ride-sharing service that was launched in Philadelphia Friday despite a ban from the Philadelphia Parking Authority.

Customers were plentiful. But so was the backlash from regulators, who sent a series of curt tweets threatening to impound UberX drivers' cars - and then making good on it in a sting operation, seizing six vehicles and fining each driver $1,000.

By Monday morning, drivers were nothing if not cautious. One declined an interview, leaving an Inquirer reporter with a $7 receipt for a 13-second ride.

Another offered to ferry the reporter from Market Street East to the University of Pennsylvania under one condition: "As long as there's not a PPA agent next to you."

That driver, who identified himself only as Alex out of caution, said he had checked the reporter's Uber rating to see if she had taken any rides before.

"I'm trying to be careful," Alex said while turning down Walnut Street on Monday afternoon. "If your rating is a perfect 5, that makes me nervous."

Anyone with the default 5-star rating likely hasn't used the service much and could be a PPA employee posing as a would-be passenger, Alex explained. Uber uses a rating system where drivers rate passengers and passengers rate drivers.

Alex is a Bluetooth-wearing software developer and father from the suburbs who has been taking fares in the family minivan since he was laid off about a month ago. Until this weekend, he avoided the PPA ban by picking up passengers in the suburbs.

But UberX announced free trips for last weekend, and on Sunday afternoon, he said, the fares were "nonstop" - "One person gets out, and immediately I get pinged for the next one," he said.

Jerry, another UberX driver who ferried a reporter around the city Monday, said he had grown used to waiting for hours in the suburbs for a single request. Saturday, he worked nine hours straight in a freshly vacuumed SUV that used to belong to his mother-in-law.

He said he has tried to give passengers a more genteel experience than what comes with an average Philadelphia cab ride, and offered the reporter a bottle of water - "They will never get that in a taxicab," he said.

Jerry, who is 64, said he became an Uber driver after he had to close his family business, a West Philadelphia dry cleaners, and was then laid off from another job.

"This is my job now," he said.

He was nervous about the PPA, but was reassured by an e-mail from Uber "implying that if something happened, they would take care of it," he said. (The company promised Sunday that it would cover expenses related to the PPA crackdown.)

"Obviously I'm worried about it," he said - but added that his son had just started college: "I can't afford to be out of work."

awhelan@philly.com

215-854-2961 @aubreyjwhelan