Even firefighters also sometimes slack off when they're not responding to a call, although the responsible ones do it in a way that allows them to go from slacking off to driving off in the fire truck in a ridiculously small number of minutes (like 2). As you say, nothing wrong with that.

I once walked through a park on a fine spring day and saw an EMT team playing whiffleball using their stretcher as a backstop. Great way to wait for a call if you ask me.

Considering their low pay and high responsibility, I would never take away what little they have such as a little park time.