Have the game insert a piece of encrypted metadata into the demo file, when sent to another player to be played, the game decrypts and reads the metadata which has an md5 like ID in it with VELBHOP[randomcharacters]GAME.
That’ll verify that the demo was produced legitimately with another copy of the game, the demo could also have a log of what inputs were used while the demo was being recorded, or even a list of hooked .dlls in it.
But that all sounds a bit too extreme for the time being. I’d imagine if Bhopping were a popular competitive game, or even an “e-sport”, this kinda thing would be used to make sure demos were legit.
That brings up the question: Why isn’t bhopping that popular of a thing to do in games nowadays? Skill based movement in modern games is dead if you ask me, it’s all just clicky clicky shoot shoot these days.