SAN JOSE — A week after blasting a fellow presidential candidate for rubbing elbows with wealthy donors in a Napa County wine cave, Elizabeth Warren came to the Bay Area — to tie a 5-year-old’s shoes.

The Massachusetts senator spent Friday afternoon helping out at an East San Jose daycare, part of an effort by the influential Service Employees International Union to get presidential contenders to “walk a day” in the shoes of workers around the country.

For Warren, that meant dishing up a lunch of meatballs, helping a half-dozen toddlers with coloring, and tying the pink laces of Delia Cardozo’s shiny silver kicks.

The event marked an implicit contrast with the controversial fundraiser Warren has criticized White House rival Pete Buttigieg for holding in Napa, which emerged as a focal point of last week’s debate. But Warren on Friday declined to answer a question about her own history of holding pricey fundraisers — including at least one at a winery — while she was running for Senate.

Instead, she talked up her plan to provide low-cost child care to every kid in America, and said she would help child care workers unionize for better pay and benefits.

“The best place we can invest is in our children,” she said. While “people with lots of money” can afford early education, “we should be doing that for every single one of our babies.”

Warren visited Wise and Wonderful Daycare and Preschool, a bilingual Spanish and English center that Rosa Carreño has run out of her home for more than 18 years.

The senator became Carreño’s assistant for the afternoon, kneeling down on the ground of her backyard to play with the kids’ plastic foods and quiz them on colors and numbers. Later, sitting in a tiny chair alongside the toddlers, she repeated the Spanish vocabulary for their lunch menu along with them, and urged the children to finish all their milk.

“Does your baby have a name?” she asked one girl holding a doll, while Carreño blew another boy’s nose. “Not yet? That’s okay.”

Warren’s universal child care plan would send federal funding to locally run daycares and preschools, making child care free for low-income families and capping costs at seven percent of every family’s income. It would also require providers to be paid at a similar level to public school teachers.

The proposal would cost $70 billion a year, according to an analysis by Moody’s, and be paid for by a new wealth tax on the fortunes of the richest Americans.

Warren also said she wanted to follow California’s lead when it came to organizing child care workers. A new law signed by Gov. Gavin Newsom this year that goes into effect Jan. 1 will allow self-employed child care providers like Carreño to form a union and fight for better wages and benefits. Organizers expect tens of thousands of self-employed child care workers to unionize in the first few months of 2020.

Warren vowed that she would allow child care workers around the country to organize with an executive action from the Department of Labor, instead of waiting for Congress to change laws preventing unionization in the industry.

“We’re going to break the mold from before on what is a unionizable job — we’re going to expand it to fit the 21st-century workforce,” she told a group of California child care workers, speaking under Carreño’s backyard tangerine tree. “Stop exploiting the people, largely women, largely black and brown women, who do this work.”

More than half of child care workers in California currently get such little pay that they rely on public assistance like food stamps, according to a Stanford University report.

The event was part of the endorsement process for SEIU, which represents 2 million employees around the country. Other current and former candidates such as Sens. Bernie Sanders and Kamala Harris have already spent a day shadowing workers elsewhere in the U.S., and SEIU President Mary Kay Henry said she expected every major contender would do the same.

“It’s really important for working people to see that presidential candidates understand their daily lives and struggles,” Henry said. She said allowing 2 million child care workers around the country to unionize would be “transformative” for the industry.

The nod from the powerful union would be a big help for any White House hopeful, coming with organizing muscle around the country.

Warren, who drew 6,500 people to a rally in Oakland earlier this year, was in the Bay Area after spending Christmas with her daughter and son-in-law, who live in Southern California.

While other campaigns have typically tacked on high-dollar fundraisers to their schedule when they visit the region, Warren — as well as Sanders — has sworn off such events, saying it’s unfair to give the wealthy more access to presidential wannabes. Citing Buttigieg’s recent fundraiser at a winery in Rutherford, she declared at last week’s debate that “billionaires in wine caves should not pick the next president of the United States.”

But Buttigieg and other Warren critics have pointed out that she also followed the high-dollar fundraising circuit during her campaigns for Senate in 2012 and 2018.

Last year, for example, she held a fundraiser at a Boston winery where donors who gave the maximum of $2,700 each were invited to a VIP photo reception, the Associated Press reported. And in 2017, she headlined another event at a fancy San Francisco restaurant that features a dining area in a “wine vault.”

Earlier this year, Warren transferred $10 million that was left over from her Senate bids to her White House campaign, giving her an important early boost.

Warren declined to answer questions about her Senate fundraisers as she hurried out of the daycare to a waiting car.

Also on Friday, Warren’s campaign announced that she had raised $17 million so far in the last three months of the year — a substantial drop from her $24.6 million haul between July and September. But she said she hoped to grow that number to $20 million by the Dec. 31 fundraising deadline, and the unusual move of revealing her fundraising total early was aimed at encouraging supporters to give.

Morgan Pringle, a child care worker in Contra Costa County who’s still deciding which candidate to support, said she found Warren down-to-earth and thought her ideas about the industry were impressive.

“It’s nice to hear somebody have an actual action plan,” she said. “For years, we’ve heard other people talk about this, but she has the specifics down.”