Why not just have an invisible barrier...?
We had one. I deemed that it's pretty silly. In real dodgeball, there's nothing stopping you from crossing the line.
Invisible note: A ball can be grabbed from both sides with a 1x thick wall
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Separate teams? Kind of inconvient if you get penalized for accidentally killing someone.
If somebody really wanted to they could kill the other 3 members of their team, and leave themselves open for an easy win. If there wasn't a rule about teamkilling there wouldn't be much we could do besides give the other team the win, considering this is a tournament.
First of all, i would hope that your teams would be professional enough not to do that.
If the teams are professional enough not to try to escape, then why can't they be professional enough not to cross the middle line, or not to teamkill?
Besides, I don't see how you can accidentally kill a member of your team when balls lose lethality after a bounce.
Secondly, you have to have your back turned and that would make you a ridiculously easy target.
No you don't.