Serendipity was not on the side of a Minneapolis taxicab driver a week ago Saturday night when he refused to accept a credit card and told his passenger to pay with cash.

Bad move on the part of the cabbie, who lost his fare and was slapped with a $200 fine when an undercover Minneapolis business license inspector on a bicycle happened upon the scene as the transaction was going down.

The incident brought to light the rules regarding how riders can pay their fares. Of course, cash is an option, but all cabdrivers are required to have credit card machines and accept plastic as payment. If they don't have the machines, a cab can be taken out of service, said Jose Velez, an inspector with the city's Licenses and Consumer Services division.

"The vast majority of drivers do a good job and follow the rules," Velez said. "They are hardworking and trying to put food on the table. I respect the job they do."

Velez says the city does receive some complaints phoned into its 311 line, and every so often Velez will catch one skirting the regulations while out on patrol.

This incident played out when Star Tribune photographer Aaron Lavinsky hailed a Viking Cab at Historic Hall's Island in northeast Minneapolis around 8 p.m. His destination was the paper's downtown headquarters. Lavinsky was quoted a $15 fare, which he says should have been closer to $11. Lavinsky handed his credit card to the cabbie, who in return told him "cash only, no credit," and instructed the photographer to hit a nearby ATM.

As Lavinsky returned to the cab, Velez pulled up and noticed the cab illegally blocking a crosswalk and told the driver to move. Lavinsky told Velez "that would not have been a problem if he took credit cards like everyone else in 2015."

That caught Velez's attention. Upon investigation, Velez found the driver did have a credit card machine in the car and was not displaying his Minneapolis taxi license. Velez gave the driver a $200 fine and a warning. He forgave the crosswalk violation.

"The driver should have taken the credit card; the transaction would have gone smoother," Velez said. "We are here to make sure cabs are meeting code. We're here to make sure they are following regulations."

A man who answered the phone at Viking Cab said his drivers do accept credit cards as required and didn't know why the driver did not.

Karma was on Lavinsky's side; Velez also told the cabdriver to cancel the fare.

"It was totally insane," Lavinsky said. "This guy was ripping me off, in this perfect moment this bicyclist rolls up. Turns out he was a cop. I was flabbergasted. Now I know why people like Uber and Lyft."

What's with the hole in the I-35W noise wall?

Reader Drew Christensen has noticed the construction work that has been going on for several months around the sound barrier on the southbound side of I-35W at the exits for 35th and 36th streets. There is a very large pipe sitting near the site, like a cistern. What's going on there?

MnDOT is building an access shaft to a stormwater tunnel about 125 feet beneath I-35W. The tunnel needs sealing and other maintenance work, MnDOT spokesman Nick Carpenter said. The shaft is being constructed between I-35W and the sound wall. Work will resume this fall.