What's up with these Fitness Centers?

I am on a job assignment in Stockholm Sweden for a few years (can't
wait to get back to Colorado). The weather has gotten so bad and
daylight in such short supply that I've started going to spinners
classes at a local gym. However, the classes are at odd times and only
30 minutes!

So I just went into the room with the spinners bikes, put on my iPod
at 115 decibles and made my own workout.... till...they came in and
asked me to get out. They said it had to do with insurance.

Any of you know the real skinny on this? Why would these machines have
a different insurance than the weight machines or the other aerobics
machines? Any ideas?