I know this is a major bump, but since I’m the Original Poster, there are exceptions. In 5th grade, the local library was hosting a science demonstration in the schools library using a fog machine. They brought over Air vortex cannons and homemade ones using a trash bags and brute trash cans. It was amusing what they were doing, but I also noticed that they shot the fog close to the duct detectors in the library ceilings, I even saw one of the fog rings go inside the vent.
About 30 minutes after we left the library and we were in class, the fire alarm rang and we all evacuated like usual. Later, we saw some firemen talking to the librarians from the public library about what they did, and told them how they set off the alarm system. This was probably the last time they did that in the school because of that.