"Silly Bubble"
I thought of a lore explanation for a tournament barrier....
It's an arcade game, sometimes you just have to shrug and say “It's just a game...” and accept something that you can easily poke holes in. You try to be a consistent and “realistic” as possible, but sometimes the game or the laws of reality make that impossible. There are things that even “you are in the wrong Place to understand” doesn't adequately explain. Or, if you prefer Babylon 5 too the PDU... “You have to surrender to toc.”
The good part of this explanation is that modern gamers already know the concept from Star Wars lore. Like most universes, you would say that combat only happens at sublight speed. Ships can force a fight with an “Interdiction Field”. The “Energy Barrier” map edge is the inner wall of the “interdiction field” used to pull another ship out of warp to fight it. At least it is assumed too fight... it would be considered “rude” to do this to someone just as a joke or something.
Then, in your story, try to gloss-over the “Interdiction Field” and avoid talking about it as much as possible. Or, if you want to go PDU style... turn it into a running joke of self-deprecating humor about all of the different ways that it isn't actually realistic;-)
So as just a first thought, maybe each race uses a different word for the “Bubble Environment” of a fight in the SCO universe. Like *Dance*/Orz in SC2. There are a LOT of words for a... circle, sphere, bubble, orb, circumference, radius, round thing, balloon, planet, ball. One race might express a sphere mathematically... anything that works. And they all share the same opinion, you guys blew it on consistency with this one! It's really easy for the sci-fi buffs to pop Stardock's silly bubble!
Haha!