Some have said using the distress signal of an upside-down flag is akin to yelling fire in a crowded theater. There is a story - haven't snoped it yet - that a school's safety patrol, tasked with the raising and lowering of the US Flag at school, made a mistake and sent it up blue field down. Someone saw it and called the police who responded. The kids got quite a grilling. That actually would be a good signal for a school in trouble so better not to dilute it. There are plenty of other ways to express your feelings.