"Anything can happen. You don't know who you're getting into the cab with," Lt. Mark Dubose of the Taxi and Limousine Commission said.
Investigators say New Yorkers and tourists hopped into the car with 55 year old Sui Hua Tan of Queens.
His clandestine cab was pulled over in Rego Park Queens at 5:30 a.m. by TLC officers, who knew it was bogus just by looking at the plates.
"It wasn't TLC plates. It was regular plates like you have on your personal car," Dubose said.
There were other dead giveaways such as no medallion on the hood, no meter on the dashboard and no credit card machine or taxi tv.
Tan was once a licensed cabbie, but the TLC said it lapsed four years ago.
"This guy is out here. He's operating for hire. He has no license to do so, which is putting passengers in danger. If he gets in an accident, they're at a loss," Dubose said.
"It's not good. That's not good. There are reason for the laws and when people don't abide in them, there are problems always," East Side resident John Luke said.
"He should be fined. I don't know about arrested. Just a stiff fine, so he learns his lesson," Silvia Casasnovas said.