Wow.

I don't teach indoor cycling (and I'm *really* glad to have the bikes' long crankarms and my knees as an excuse not to), but there's a contingent of people who show up for my strength and step classes and don't pay attention. In that situation, it's "merely" rude and distracting to the other participants.

But in a spin class, where bikes are nearly always limited, it's more than rude to take a bike that someone else could be using and then not participate in the class. If I were the instructor in that situation, I'd speak to the person after class, and if they continued to do that I might even speak to my program coordinator.