You got it right, they need adult *supervision*.

In the words of Inigo Montoya: "You keep using that word. I do not think it means what you think it means."

Supervision doesn't mean hovering. It doesn't mean that you child shouldn't ever be allowed to mess up or do something dumb (cutting one's hair is just dumb, not criminal.)

Ultimately, kids must be allowed to make errors. The key is to allow them to make errors that won't ruin them in the process.

As for the falling on scissors: it could happen. I once looked at the morbidity statistics, and the largest cause of death for kids was the grand old automobile, far and away a HUGE killer. Next came water. Scissors weren't anywhere on the top 25.

Stop panicking. Relax. Enjoy the kids and their goofy haircuts. Get mad, but remember that it isn't the end of the world.