Butt-dial is characterized by calling someone unexpectedly when you sit on your phone. A woman called SWAT after her husband butt dialed her on his way to work, thinking he was being held hostage.
Over the open phone line she sat listening, she heard the lyric to a rap song and became concerned. Armed with automatic weapons and wearing bulletproof vests, SWAT team members circled the school [where the husband works] about 5 pm, searching for a reported gunman who might be holding a hostage. The all-clear sounded nearly three hours later, after the man was found safe at home by police.
Usually if the receiver simply hang up the line, they can call the person back. But in this situation the wife wasn’t sure her husband wasn’t a hostage. Then again if he was, she wouldn’t want to alert the perpetrators.