If you shoot a disguised person but he escaped and didn’t die, are you proven? Because he was disguised.... I am assuming you aren’t until you find the body like someone holding a t weapon but idk
Only traitors can be disguised so yeah, you're proven. Make sure people aren't tricking you by shooting near their T buddies while yelling "bang bang" to make you think they're proven.
You can be considered proven, but proven status isn't an official part of any of our rules, so take with it what you want. Players can still kill you regardless.