Louis C.K.’s return to stand-up came and went, in the form of a 15-minute surprise set that only about a hundred people witnessed.

The comic had been publicly silent since he admitted in November that five women’s allegations of sexual misconduct against him — including his masturbating in front of them — “are true.”

“I have spent my long and lucky career talking and saying anything I want,” C.K. said in response to a New York Times investigation. “I will now step back and take a long time to listen.”

On Sunday, he performed an unscheduled set at the Comedy Cellar, a New York comedy institution that C.K. used to frequent and that’s known for attracting big-name drop-ins.

Cellar owner Noam Dworman said he found out about the set the next morning via text messages that employees sent after he had put his kids to bed. But he did watch a tape of the set and said that when the host announced C.K., the audience broke out into “sustained applause,” with some folks “giving a little bit extra,” as if to show they “wanted to hear what he had to say.”

C.K. did new material but didn’t address his past misdeeds and subsequent apology.

News of the set, first reported Tuesday by the Times, sparked a larger conversation on social media and elsewhere about men who have quietly returned to their professions after stepping out of the limelight following sexual misconduct allegations. (C.K.’s is the rare instance in which he eventually admitted wrongdoing, after years of denying rumors.)

Comedy bookers and club owners are grappling with how to react. Are they the gatekeepers? What responsibility do they have, as the public reckons with a wave of sexual misconduct revelations?

“I think too many people are interpreting it as a reflection of how we feel or don’t feel about what Louis was accused of, or admitted to doing. It’s not really about that,” Dworman said of his club allowing C.K. to drop in. “It’s more of an ACLU approach, which I’ve always had, which is to say that we’re a platform for comedy, that handing out punishments is something that institutions of courts of law do.”

And while “every club owner, it’s their business and they can draw their own lines,” Dworman said, “the public needs to be careful about expecting that the club owner is obligated to draw that line for them, as opposed to saying, ‘I don’t want to see Louis C.K., I won’t go see him.’ ”

Unlike in other professional settings, stand-ups can operate like independent contractors. The very famous ones can produce their own live shows and have massive email lists they can use to contact their fans. And, as with C.K’s drop-in set, sometimes comics perform simply to work out material, rather than to get paid.

In recent weeks, Aziz Ansari has also been performing at abruptly announced shows around the country in sizable venues as part of his “Working Out New Material” tour. The comic had retreated after being accused anonymously in January of sexual impropriety. (He said that his encounter with a woman “by all indications was completely consensual.”)

For Marshall Chiles, owner of Atlanta’s Laughing Skull Lounge and Laughing Skull Comedy Festival, the questions when it comes to comics like C.K. are: “Is he going to be doing hate speech? Is he going to be encouraging that behavior, or is he discouraging that behavior, even with his transgressions? . . . [What] if he had this amazing 15-minute bit of the errors of his ways?”

While Chiles says he’ll never tell a comic what to say onstage, “there is a responsibility of some sense. If you got a platform, a comedy club pulling 1,000 people a week, you have a responsibility that what’s onstage is not hurting society.”

“If he hadn’t apologized, and he was trying to fight it or justify it, I would not be tolerant of him onstage,” Chile said. “The fact that he handled it the way he did, I believe in giving people second chances. I’ve made mistakes.”

Dworman was surprised that C.K. returned so soon, and in such a setting, and that he didn’t address the controversy at all. He suspects audiences want C.K. to, “like Richard Pryor, talk about his past.”

“In comedy there is a long history of comedians with pasts that people disapproved of, talking about that stuff onstage and being lauded for that,” Dworman said. “Richard Pryor famously talked about all these terrible things he had done and nobody had ever thought that somebody shouldn’t put Richard Pryor on. That didn’t mean they approved of” his actions.

On Tuesday, many comics took to Twitter to post their shock, and disappointment, with C.K.’s return.

“The fact that Louis, a comedian whose whole thing is plumbing the depths of his own psyche, apparently didn’t mention his most recent, famous news in his surprise set tells you all you need to know about his desire for ‘redemption,’ right?” tweeted comedian Paul F. Tompkins.

Comedian Jackie Kashian tweeted that she didn’t think C.K. would perform stand-up until he wrote a bit about his actions.

“Make THAT funny is what I thought would be his comeback,” she wrote.

It’s unclear whether C.K. will hit the stage again anytime soon. But he’s now broken his silence, almost 10 months after he decided to “take a long time to listen.”

As New York comic Sarah Lazarus wrote in a viral tweet, “I’m still on the same shampoo bottle as when louis ck’s time out started.”

Correction: An earlier version of this article misspelled Paul F. Tompkins’s last name. The story has been updated.