Sitting on sidewalk =boom?

So me and my parents went out for a jog around a park. After i ran 2 laps i squat down on the sidewalk, then my dad said: Don't sit on the sidewalk, you'll make the gas pipes explode. I mean, sure that's possible in the RIGHT circumstances, but... you see what i mean?

The concrete/cement sidewalk and a bunch of dirt is over the

supposed pipes if they are there, and the pipes must be strong

enough, or else they wouldn't use it. Then they said, Don't they

teach you this in school? Yeah.... By the way, they're oriental

chinese. I just wanted to get this thought out.