I guess Leorio is the kind of a doctor that if he gives you doctor's orders, you aren't going to decline.

Ging was taking the hit on purpose, no doubt. He probably saw it as the easiest way to end the disorder. Being Ging, he wouldn't give a shit about being seen knocked down. I imagine he got up immediately after Leorio left, as if nothing happened. Unless he wanted to skip the rest of the event by taking a nap on the floor...