It's a fantasy role-playing game.

DM: You are Percival de Rolo, a human gunslinger . You are the member of the famous group of adventurers. Previously, Percy takes some shots at Ripley and manages to knock her over. Grog attacks one of the gunslingers.
DM: Actually, because she's on the ground it's at disadvantage. Any ranged attacks against prone people.
Player: Even with Sharpshooter? Even with standard Sharpshooter bonus of ignore three-quarter cover?
DM: It's not so much cover, it's more the fact that they're a smaller target to hit because they're closer to the ground.
Player: So the full range Sharpshooter ignore three-quarter cover would not cancel that out?
DM: It's not cover that gives her the bonus.
Player: The whole theory being that it's easier to hit smaller targets.
DM: Right, it affects cover, it doesn't affect her being a smaller target in general to hit. It's the way the rule works.
Player: That's okay. She's down. What am I going to do? I'm not even going to pretend. I'll burn a point of grit to also ignore that.
DM: Okay, there you go. It's a straight attack roll.
Player: That's probably not going to hit. Let's see. 14.
DM: 14 does not hit. It scoots past her and slams into the tree behind her. You see the splintering of petrified bark.
Player: I throw my gun behind on my shoulder, and I'm going to head to my right to try to get some cover with that tree.
DM: Around Keyleth?
