But Sweet, who first proposed allowing coffee on trains in April as a potential way of increasing revenue, accused staff members of coming up with "the absolute worst-case scenario" possible and vowed to continue pursuing the idea.
The proposal was on the BART board of directors' agenda today only as an informational item, and Sweet said she hopes to bring it back again. "I won't let this die yet," she said.
The staff report predicts that it would cost $5.4 million a year to police and clean its cars and stations if the agency allowed passengers to bring coffee on trains.
Included in that total would be $1.8 million for 12 additional police officers and nearly $1.2 million for 14 additional station cleaners.
There would also be additional costs for replacing seat covers and for cleaning carpets on BART cars, according to the report.
In addition, the report says 45 percent of BART riders who participated in a survey said they want the transit agency to retain its current policy of not allowing beverages. Only 36 percent wanted the policy changed to allow drinks in licensed mugs.
Sweet's idea is for concessionaires who sell coffee at BART stations to also sell special mugs that would be allowed on trains. BART would receive revenue from the mug sales.
But the report says nearly two-thirds of riders who participated in a survey said they were unlikely to purchase and use such a container.
The staff report also says a policy change would put BART directly at odds with nearly all connecting transit operators, who continue to have a policy of not allowing beverages and food.
A change could cause rider confusion and increased problems on connecting services, particularly at stations shared by BART and other agencies, the report says.
Board President Gail Murray said she's been "intrigued" by the possibility of allowing passengers to drink coffee as a way of making the system more customer-friendly but most passengers who have contacted her are against the idea.
Murray also said BART trains are getting more crowded and she thinks allowing coffee on trains would only increase tensions during busy commuting hours and "would be another irritant to people who don't like it."
"Most of our customers are responsible but we also have some irresponsible customers" who could cause problems, Murray said.
She said she thinks BART would be able to spend less than $5.4 million a year to deal with change in the drinking policy but that she still thinks the costs of the change would far exceed any revenues that would be generated.
"For all those reasons, I'm inclined to stick with our current policy," Murray said.
Directors Joel Keller, James Fang, Bob Franklin and Thomas Blalock also said they're against allowing coffee on BART trains. Director Tom Radulovich was the only director to join Sweet in supporting the idea.
Sweet said after the meeting, "Fortunately there wasn't a vote today."
But she said most of the BART riders who have contacted her support allowing coffee on BART.
"If we can make money off of it, let's do it," she said.
Metropolitan Coffee and Concession has opened kiosks that sell Peet's coffee at four BART stations so far: Embarcadero and Montgomery in San Francisco, downtown Berkeley and Pittsburg-Bay Point.
BART spokesman Linton Johnson said four more stations will be added in the near future, including the Civic Center and Powell stations in San Francisco and the Daly City station.
He said the other one probably will be Pleasant Hill, but a final decision hasn't been made yet.
Keller said it's "a contradiction" to sell coffee at BART stations but not allow passengers to bring coffee on trains.
He said he doesn't think passengers should be allowed to drink coffee on trains so he proposed ending BART's contract with Metropolitan Coffee and Concession when its current contract expires.