thats not a localized issue , half of USA dont know how to joust safely , they even discussing doing side way jousts or face off to replace the oh so lethal OG joust.
i vouch for a clarification of the joust as well , its a old concept as you said but isnt clear to everyone / new players.
the escalation solution you proposing to silence a bully is also not very helpful , we could also have this issue in pick ups.
you asked :
what happens if at some point a player crosses the imaginary middle. How far is far enough? Do you see what I’m saying? Are we going to have to draw a line down the middle now when we build courts?
imaginary line is enough , since the real line to not cross is the other player trajectory. players have to adopt a straight trajectory not curving as they go for the ball.
once the ball is possessed , the players jousting are still due to respect each others trajectory.
if you want to concede thhe joust dont go further than the top of the crease.
i would add as well that non jousting players have to remain at the top of the crease as well until the joust is over to not set up an additional obstacle , this is what is done usually but its not written black on white neither