When it comes to working out there is some etiquette involved, like the 30 minute rule. BUT what if you are training for something and need more than 30 minutes?
Avoid going at off peak times like early morning or after work. If you are training for a race try 30 minutes on a tread mill and spend your time other places like the elliptical or bike. And if you are the one that needs the equipment then you could try to tell the person you are waiting but the safer bet is to tell the person at the front desk and let them enforce the rules.