Planet Fitness puts rules in place that keep 'lunks' out of the gym, as in, no deadlifts, no grunting, no water jugs, etc
The concept behind it is that it intimidates others at the gym and creates a less comfortable environment
But what if you were to crank out a tempo run at 5min pace on their treadmills? Surely they wouldn't think you a lunk initially because of your lean frame, but would they react in any way to maxing out treadmills