Photo: Amy Osborne / Special To The Chronicle Photo: Jim Taylor, Courtesy KCBS

For the past three months BART fare inspectors and police officers have been conducting sweeps of morning trains at San Francisco’s Embarcadero Station and ejecting riders who are unable to show proof of payment.

BART police estimate that, on average, the sweeps of eastbound trains have resulted in about 75 to 100 people being removed from the trains during each of the 36 sweeps made to date.

“The fare-enforcement actions have been happening at the start of our morning service, which is about 5 a.m.,” BART spokesman Chris Filippi said. “It can be a combination of up to 14 officers and fare inspectors, but the total number and ratio can change from day to day,” depending on what resources are available.

So far the sweeps have been only at the Embarcadero Station, which has the most passenger traffic of any of BART’s 48 stations. A full sweep of a train typically takes three to five minutes. BART stepped up enforcement in September and hasn’t set an end date.

“That will be determined by the effectiveness of the effort,” Filippi said.

Adult fare-evaders are subject to a $75 citation; a juvenile citation is $55.

But the focus of the morning sweeps is on “ejecting violators and not necessarily issuing administrative citations,” Filippi said.

BART estimates fare evaders cost the cash-strapped transit agency $25 million a year in lost revenue. And the gate jumpers often bring other bad behavior — panhandling, taking up seats by spreading out and sleeping, and verbal and physical assaults — with them, making BART riders feel unsafe and contributing to the system’s ongoing slump in ridership.

But unlike past fare-evasion enforcement actions, which have at times been publicized and conducted at station entrances, the Embarcadero sweeps are being done underground on the platform — with no publicity.

And BART apparently has no intention of publicizing future sweeps. Here’s the response we got to a request that we be able to tag along and take pictures.

“We feel providing advance notice of a fare inspection activity for photographic purposes would be unfair to individuals who are escorted out of the trains and stations,” said Jim Allison, BART media relations manager.

Indeed, the sweeps might have stayed under the radar had not KCBS radio reporter Jim Taylor found himself in the middle of one when going home to Berkeley early Monday morning. He quickly phoned in a live report for the morning news.

“It was totally by accident,” Taylor said. “I had been at the station doing a report about flight delays and was at the Embarcadero Station at 6 a.m.

“There were about a dozen cops and ticket checkers on the platform. They came on the train and checked each and every person for a fare,” Taylor said. “If someone was not in compliance, they were taken off the train and walked upstairs.”

BART board President Bevan Dufty said he only learned of the sweeps when we called him Friday.

“What’s happening is that people are seeking shelter on the trains and wind up at the end of the line with nowhere to go,” Dufty said after he contacted BART staff for details. “Spending all day or night on a train isn’t getting people anywhere.”

The prosecution rests: “I’m not a billionaire,” California Sen. Kamala Harris declared when she exited the Democratic presidential nomination race last week, but she does have plenty of wealthy friends, including a group that had just ponied up $1 million for a TV ad campaign that will never be seen.

As luck and politics would have it, the ad campaign was scheduled to launch less than 24 hours after Harris dropped out.

“It was going to be the biggest TV campaign in the race by a non-billionaire,” San Francisco campaign consultant Dan Newman said.

Newman and Brian Brokaw, who was Harris’ campaign manager during her successful 2010 race for attorney general, had teamed up with major Democratic donor Quinn Delaney and other Harris supporters to form the independent political action committee People Standing Strong. They were not part of the Harris campaign.

With Delaney’s help, the group raised $1 million for a TV ad to be broadcast in Iowa, which holds the first caucus of the primary season.

The ad, which highlighted Harris’ legal roles, was to be shown on 15 TV and cable channels with the goal of re-establishing her image as a take-no-prisoners prosecutor who could take on President Trump.

The ad featured clips of Harris grilling Supreme Court Justice Brett Kavanaugh during his confirmation hearings, as well as Attorney General William Barr and former Attorney General Jeff Sessions with a series of just “answer yes or no” questions.

The ad was focus-group tested on Democratic voters and found to be the most effective message to give Harris a badly needed boost in Iowa.

“We had placed the first week buy for $500,000 and were ready for the second $500,000 with more expected to come,” Newman said.

Under federal election law, independent PACs are barred from coordinating their efforts with the candidate’s campaign. So, while Newman and company knew from news reports that the Harris machine was faltering, they had no idea that Harris would pull the plug on Tuesday morning.

But pull out she did, saying, “I can’t fund my own campaign. And as the campaign has gone on, it’s become harder and harder to raise the money we need to compete.”

That left Newman and Brokaw to scramble for refunds on an ad that TV viewers never saw.

“It only lives online,” Newman said.

Kind of like Harris’ presidential bid.

San Francisco Chronicle columnist Phil Matier appears Sundays and Wednesdays. Matier can be seen on the KGO-TV morning and evening news and can also be heard on KCBS radio Monday through Friday at 7:50 a.m. and 5:50 p.m. Got a tip? Call 415-777-8815, or email pmatier@sfchronicle.com. Twitter: @philmatier