It wasn't trespassing though, Tybalt didn't see the MC until he was at the front gate and he told him to leave on top of insulting him and then striking him. The MC reacted out of self defense one time, then left immediately. That would be viewed as someone not wanting the situation to escalate any further which would work in his favor. IF other guests could remember him being inside, so what? None of them knew he wasn't allowed there and it was already stated by Jill that he's one of her guests and Tybalt should show some respect for that since she's a member of the preps. So far, Tybalt has only done the exact opposite of that, the MC and Derek's absurd practical jokes notwithstanding. Why anyone wants to defend Tybalt though considering how creepy the guy is in the game, confounds the hell out of me. Even his own mother seems to barely tolerate him considering how rude he was to her at the party and she told him off for it.