They were further stunned when the couple asked if they could push the crib up to one of their sidewalk cafe tables and have their child hang out in it while they ate brunch.
An influx of families has been drawn to the condo developments on the Williamsburg waterfront, while longer-term residents have started having children, and as a result places that were once known for serving beer to struggling artists are now concerned about stroller traffic jams.
"That certainly was a first," said Rosarita's daytime manager Susie Kenny. "We were laughing all day. It was a highlight."
Kenny added that she wasn't sure if the crib "passed fire code," but didn't want to turn the couple away after they had gone to the trouble of pushing it down street.
At Surf Bar, a classic Williamsburg pub and restaurant that serves chowder and features sand on the floors, a family let their two children treat the surf shack like a beach.
"One kid buried himself up to his neck in sand," said waiter Santiago Cardena, 24. "Every time I went to carry something back, he was deeper in."
Cardena added that the two kids, who he estimated were about 6 or 7 years old, also used water from the table to make sand castles.
People taking their children out for food and drinks in the area have become so prevalent that Parish Hall, on North Third Street, which was started by owners of Egg, has booster seats already attached to chairs in the rear section of the eatery.
"So it's business in front, babies in the back," said manager Charlie Karrell. "All the people we served at Egg, now they're having kids."
Karrell added that he is sometimes still confused about how to handle customers with children. He recently offered some crayons to a couple who brought their baby with them to the meal.
"No, he's just going to eat them," Karrell recalled the parents telling him.
The influx of children also brought some unexpected messes.
With the children's finicky eating habits, some parents will bring Cheerios for their kids to snack on while they eat more adult-oriented dinners.
"Cheerios make a big mess," Karrell said, "but we're happy for it."
Some Williamsburg parents said even though the neighborhood has become more child friendly there was still a feeling of embarrassment if their kids were misbehaving or they had to make a special request.
"Eating out becomes this balancing act of keeping your kid happy and getting food in your mouth," said Vita Rayhkman, 32, who was sitting outside of Fabiane's Cafe and Pastry with her 7-month-old daughter, Nina.
The challenges of going out as a parent have been made somewhat easier by new technologies.
"Now everybody just puts an iPad in front of them, sadly," Rayhkman said. "It's the solution du jour."
Cheyenne Vesper, who has lived in Williamsburg since 2000 and has two children, said there are "tons more parents" in the neighborhood. While she finds most local restaurants very accommodating, there are still a few occasions when she has felt unwelcome.
"[They were] so over the stroller," said Vesper, 38, about taking her 9-month-old baby to Maison Premiere on Bedford Avenue. "There's not a lot of room."
The next time she went with her child in a baby carrier instead, and found them to be much more gracious.
At least one establishment has had to keep some customers from putting their children in potential danger. Viva Toro, a cowboy-inspired restaurant with a mechanical bull on Berry Street, has had to discourage multiple parents from allowing their children on the ride.
"Parents want to carry kids while riding the bull," said Ricardo Ordonez, a manager at Viva Toro.
While Ordonez said riding the bull is not allowed, the restaurant does allow parents to take pictures on the bull with their children while it is stationary.
But despite the rare dangers, most local workers treated the neighborhood's changing demographics with good spirit.
"We welcome babies," Karrell said. "All our biological clocks are ticking."