Link at Gopher Sports about PE teacher trying to incorporate bikes into school curriculum

Your school suffers from the challenges of incorporating the bikes into the gym class (I've never heard of anyone successfully doing this), combined with some combination of poor, inadequate, or unqualified/undertrained supervision.

I teach music, and the challenge of kids that smash stuff up for fun is real. I've had to teach guitar class to middle school students that preferred to detune the strings, strum like gorillas until something broke, and drop pics into the bodies of the guitars.

In any school setting, you simply need to back up to some level of experience that you can control. This might require in your case a written safety and bike operation quiz. Put tape on the gym floor with a course. Use scrap lumber or other material to build some (low) obstacles for them to ride over or across. The carrot is that when they can handle themselves in the gym, they can go outside to say a course in the parking lot, then more. Offenders could sit with the other teacher.