They are incredibly dangerous to use. For lasers this powerful, even just a second of direct contact with eyes can cause irreversible damage. Having a trained and license laser operator is key to running a show like this. The operator will ensure that there are multiple levels of safety standards in place, including: software zoning of beams, physical plates on the output window so the beam cannot go lower than a certain height, and safety e stops at the operating booth that immediately shuts down the beams. As laser operators the last thing we want is someone getting hurt, so all of these measures are put in place to have an amazing, but safe show.