http://www.planetout.com/news/history/archive/10251999.htmlFrom the very beginning, tearooms fell under police scrutiny. The first arrests in Manhattan occurred soon after the opening of public facilities in 1896. To circumvent arrest, one man would often remain outside the restroom as a lookout, warning those inside if a policeman was approaching. An arrest could ruin a man's life: When newspapers published the names and addresses of those arrested, men lost families, jobs, and housing.
More intricate surveillance techniques soon came into use. In 1920 in Boise, the men's room at one downtown building, the Boise Valley Traction Company, was a popular tearoom. During the summer of that year, the management hired one of its employees to spy through a hole in the men's room ceiling. His surveillance resulted in the arrest and conviction of two men, who were sentenced to five years each in the Idaho State Prison.
Entrapment was another method for policing tearoom sex. As early as the 1910s in New York, plainclothes officers entered park toilets and subway washrooms, pretending to be cruising for sex. In some cases, police decoys blackmailed men for hush money. In the early 1960s, a man in St. Louis admitted that he had made eight such payoffs to undercover cops, ranging in amount from $60 to $300 each, in order to avoid arrest.