In an interview on Friday, Mr. Sliwa said he had planned to sit shiva for eight days — one more than the customary seven — but his wife went out of town, so he had to look after their cats, and then the Knicks won Game 4 of the finals and he had to patrol the streets with the Guardian Angels. So in the end, his intended eight-day mourning period turned into two.

But he made sure to make the most of them. Decked out in his signature red beret and a red windbreaker with “Curtis Sliwa for NYC Mayor” stitched in white thread, he said he is often mistaken for a lobster himself. As he enjoyed his second consecutive day of all-you-can-eat shrimp on Friday, he went out of his way to inform his fellow diners that Red Lobster was closing.

“Sunday night, 11 p.m.,” he told them, dismayed.

“Is he the owner?” one customer asked a reporter.

Mr. Sliwa is not, in fact, affiliated with Red Lobster in any official capacity. But for the past week, he has taken it upon himself to spread the word of the Times Square location’s closure.

Diners lined up to take photos with him on Friday in between rounds of shrimp; a Red Lobster waitress was even among those waiting their turn. Mr. Sliwa said he was worried that the demise of Red Lobster was a bad omen, that eating out was becoming too expensive, even at what he considered to be a family-friendly restaurant.

“I think this is a harbinger of really bad times,” he said.

For at least one group of customers, Red Lobster used to be synonymous with good times. Bennett Wilson, 45, runs a film studio in Brooklyn with five friends, who have made it a tradition to take the subway up to Times Square when celebrating positive developments with the business. Most times, they even have the same server, Jose.