One concern I have, about sarging, is that I'm going to go into a set, throw a playful neg at a girl, and have her drunk, over protective, and agressive guy friend or boyfriend try to fight me or instantly blow me out of the set.

I mean, I know a lot of guys that will become angry over the slightest disrespect. And if he's her boyfriend I could see him getting nice and pissed off about any negative comment. Mystery says they will just be relieved that I'm not hitting on her. But I'm not sure.

I've known guys who will fight a guy if he looks at his girl the wrong way. And not even his girl, just a girl he came to a party with. Maybe I need to stop hanging out with assholes.

Well basically I think the set should be interested in you and respect you to an extent before you start negging people. They will all take it as a joke if you have this already apart from maybe the drunken asshole but he will then look like an idiot in front of his friends, not you. I get more aggressive when drunk but I certainly wouldn't try to start a fight over a comment like that especially if I knew it was a joke.

Read about how to improve your frame. Having people follow under your frame, your tempo. Some other things to look at would be things like just talking to them once they come in and try blowing your set. Get them in the conversation too. Just run a search on 'cockblock'
Also it's going to be hard to game a girl, with her boyfriend sitting right next to her. If you're new, don't worry about it, move on, and find more game.