Whistling in a theater is considered unlucky. When theatrical scenery began to fly in the middle of the 1600s, this belief emerged. Sailors were employed backstage as run crew because of their great expertise of ropes, rigging, and knots. They made a special whistling sound when they worked together to help passengers understand when it was time for them to go on or off of the ship.
The reason for this superstition is that if someone sounds a warning before an accident happens, it is assumed that this person was responsible for the incident. Therefore, no matter how serious the situation may be, you should never whistle or make any other noise while onstage or in front of a large audience.
This practice has been passed down through the years by word of mouth. No one wanted to be blamed for something terrible happening during your performance, so they decided from then on not to make any unusual noises.
But what happens when something unexpected does happen? Then people will think that you are responsible for causing the problem, which in this case would be whistling. So in order to clear yourself of this accusation, you have to do the exact opposite of what is suggested here: act quickly and give loud warnings if anything dangerous is about to take place.
This way nobody will blame you for anything that might happen later on during your show.
Whistling Whistling on or off stage is considered bad luck, analogous to a similar regulation for sailing ships. Whistling actors might cause them to change the set or scenery at the incorrect time, resulting in harm or death, especially if they were flying the set or backdrops in or out.
The origin of this practice is not known for certain, but it is believed to be derived from the ancient belief that the spirit of the dead can still hear whistlers and thus take revenge by causing mischief during their visits to the theater.
This rule is particularly important for singers: if an orchestra member falls ill or dies while you are singing, there is no one else to help you with the promptings if you continue with the performance. So before starting your next song, please ask yourself: "Is this safe?" If the answer is no, then stop what you are doing and find another way to go about your business.
Here are some other things you should never do in a theater: roar like a lion (or any other wild animal) or howl like a wolf; throw objects at the screen; use flashlights or lasers; stand on chairs or benches; or exit through a wrong door. These actions may frighten people and cause accidents.
In a theater, you should never whistle. Because, let's face it, there were a lot of ropes backstage and a lot of them on a ship's deck, sailors were frequently employed as stagehands in theaters. Whistling was used to signal the workers to raise or lower the ropes. So, if an actor whistles on stage, he could cause a dangerous misunderstanding between himself and one of the workers.
The reason why actors don't whistle on stage has nothing to do with being professional; it has everything to do with being considerate of other people. If an actor whistles, he might give the wrong impression to the audience, make someone fall off a rope, etc. Even if there are no ropes in the theater, still you shouldn't whistle because it can be seen as rude. Also, actors should always remember that they are being watched by others, so they should always act professionally at all times.
Another reason why actors don't whistle on stage is that it is actually very difficult to do so effectively. You need to produce a sound only audible to those nearby, so anything from a low whistle to a loud bray would do damage if heard by someone else. And even if you manage to produce such a sound, it won't necessarily mean that another person will stop what they are doing and come to your aid.
As you can see, there are many reasons why actors don't whistle on stage.