One theory: Broadway is vulnerable to boors because it is under pressure. More new shows opened this past season than at any point in the past 25 years, which means more seats to fill in a recession. In response, shows have been offering steep discounts on tickets, which can normally cost upwards of $100 apiece., an entertainment site, is promoting a “Lucky Sevens” discount that offers a “Guys and Dolls” ticket for $7.77 with the purchase of a full-price seat.

That’s the theory.  Here are the data:

The litany of misdemeanors is long. During a Saturday matinee of the Holocaust drama “Irena’s Vow,” a man walked in late and called up to actress Tovah Feldshuh to halt her monologue until he got settled. “He shouted, ‘Can you please wait a second?’ and then continued on toward his seat,” recalls Nick Ahlers, a science teacher from Newark, N.J., who was in the audience. He says the actress complied.

During a recent matinee of “God of Carnage,” which explores the lives of two couples, a woman in the mezzanine screamed, “How ’bout those Yankees!” — filling one of the play’s intense silences. At “The Norman Conquests,” an elderly man familiar with the British comedy script recited his favorite lines as the actors read them, prompting audience members to confront him at intermission. Steve Loucks, a theater blogger from Minneapolis who was sitting near the man, was stunned. “What is with people who think they’re in their own living rooms?”