Door hanger

Door hangers are often seen in hotels and other places of lodging as a means for guests to communicate with maintenance and housekeeping staff.

In multiple cases, a do not disturb sign on the door of a hotel room has been blamed for concealing a homicide, suspicious death, or other criminal activity.

[6] In 2017, mass murderer Stephen Paddock kept a "do not disturb" sign on his hotel room door, concealing ten suitcases with a stockpile of rifles and ammunition he used to commit the 2017 Las Vegas shooting.

[8][9] In 2007, Embassy Suites ran a contest allowing the public to design do not disturb signs.

This type of advertising offers a number of advantages over traditional direct mail in that the impression is "guaranteed".