Patti LuPone’s quick snatching of an audience member’s cellphone on Wednesday made her a vigilante heroine to those frustrated by breaches of theater etiquette. But the incident, at an evening performance of “Shows for Days” at Lincoln Center, also highlighted a seemingly intractable problem: What to do about people who think a darkened theater is a great place to check Facebook?

“I’m at my wit’s end,” said Ms. LuPone, who in 2009 stopped in the middle of a song in a Broadway production of “Gypsy” to berate a photograph taker.

Theaters’ standard practice is to use recorded preshow announcements, often laced with humor, to encourage the silencing of mobile devices. And once a show starts, an usher may try to quell a rule-breaking patron. In rare cases, actors like Kevin Spacey, Hugh Jackman and Laurence Fishburne, have broken the fourth wall to address silence-shattering rings during a show.

A personal touch in advance may help even more. Before the start of the intimate drama “The River,” an understudy stepped on stage and implored the audience to turn off their phones. Having an actor make the request worked, according to Susan Frankel, the general manager of Circle in the Square Theater.