All this, however, could merely be a prelude to the moment yet to come — Mr. Trump has still not set foot in New York City as president, puzzling and emboldening some protesters who see his weekend visits to his Florida estate as something of a retreat to friendlier ground. But whenever he does settle into his penthouse home atop Trump Tower, seething New Yorkers will finally be able to train their ire directly at Mr. Trump on his doorstep.

“The visual of Trump coming back to New York would be the Fifth Avenue of Manhattan flooded with people angrily protesting just about everything that Donald Trump has done — I don’t think he wants to create that visual,” said Carl Dix, whose anti-Trump group, Refuse Fascism, has been plastering the city with stickers that say “NO!” “I don’t think he wants the world to see that.”

City officials would not discuss details of security plans that will be used when Mr. Trump returns to the city or how much protecting him will cost. Between his election in November and his inauguration in January, the city spent $37 million for the more than 200 police officers on patrol each day in and around Trump Tower. The federal government has reimbursed the city about $7 million. Large protests would most likely require a bigger police presence.

“Demonstrations do have an impact on operations because we have to get those cops from somewhere,” the police commissioner, James P. O’Neill, told reporters at a news conference in response to questions about how the city would manage Mr. Trump’s return. “Short term, we can handle it, but if it continues to go on, it could have an impact on our operations.”