You're absolutely right that the story is printed in Epstein's book, and what's worse is that she doesn't have a citation for it. She doesn't even say that In "X-Year," the "X-source" said XXX. She just prints this apocryphal story without any source information, alongside other cited stories about Othello. I've emailed the publisher to pass on a source request to her, but I don't expect a response.

You should note that when Epstein's The Friendly Shakespeare was published in 1993, New York Times reviewer Michiko Kakutani criticized it, saying, "The Friendly Shakespeare appears to have been assembled quickly, and its facts are not always correct."

In the meantime, let's talk about why the story is plausible. It has to do with an instance in which a performance of a Shakespeare play didn't result in just one death ─ it resulted in the deaths of at least 25 people. I'm talking about the Astor Place Riot.

If you're interested in this topic, pick up Nigel Cliff's The Shakespeare Riots: Revenge, Drama, and Death in Nineteenth-Century America. It's a fast, readable book published in 2008, and it'll point you in the direction of more work on the topic.

The long and short of it was that on May 10, 1849, a gigantic riot broke out in New York City amid a performance of Shakespeare's Macbeth. While the play was the spark, the riot was the product of the extreme nativist sentiment present in the United States at the time. This was a moment in American history when millions of German, Irish and Austrian immigrants were pouring into the United States in the wake of the failed liberal European revolutions of 1848. Think an "Arab Spring" in the heart of Europe.

Much as Europe is reacting harshly today to the flood of Middle Eastern immigrants arriving on its shores, so did the United States react harshly to the arrival of European immigrants. There were anti-immigrant political parties (the "Know-Nothings" are the most famous), movements and, of course, riots.

At the same time, relations between the United States and Great Britain were at a low ebb. Unlike today, however, there were few outlets for nativist fervor. People could talk about problems with their friends, but they didn't have social media ─ they couldn't share their outrage in an easy way. One of the few easily accessible aspects of foreign culture in the United States were the touring theater companies that came over from Europe to perform. Theater ─ particularly Shakespearean theater ─ was big business. People wanted to be entertained just as much as they do today, and European-trained actors were considered among the best. The wealthy classes wanted to see these European-trained actors. At the same time, the working classes, filled with nativist sentiment, wanted to see American actors in these Shakespearean roles.

In 1849, the popular press was filled with the conflict between two Shakespearean actors: William Charles Macready (an English actor) and Edwin Forrest (an American actor). At first, their relationship had been good-spirited; they toured at the same time, both in Europe and the United States, both seemingly competing to see who was the better actor. When Macready came to the United States on one tour, Forrest followed behind, staging the same productions at the same time (or a few days after), encouraging the audience to decide who was best.

Forrest knew how to play the public just as well as the stage, and so when Macready came to the United States for his final tour, he was met with a storm of opposition from the working classes. In one New York City performance, outraged Americans threw a rotting sheep half at him from the balcony. At other performances, they booed and hissed the production so loudly that the actors had to perform a pantomime. They were pelted with rotting garbage and items ripped from the theater itself. Macready vowed to leave on the next boat, but he was convinced by some of New York's elites ─ including Herman Melville and Washington Irving ─ to stay for one final performance.

This proved to be a mistake.

Macready's continued presence was a rallying point for working-class nativists who prepared to disrupt the production with more of their same antics. To counter them, New York's police force was mustered and bolstered with soldiers from the state militia. When the nativists attempted to disrupt the production again, the situation turned into a riot. Up to 10,000 people filled the streets around the theater by the time the production began.

The theater was in an effective state of siege, and to clear the streets, the militia first fired into the air ─ and then into the crowd at point-blank range. Bystanders were killed along with rioters, and immigrants were killed alongside longtime Americans. The rioters called out for revenge the next day, but a march on Astor Place was disrupted by the militia, again bloodily.

Edit: Notification for /u/killcole at his/her request.