I get that there's a fluid barrier already, but my suggestion would be about placing water in side, and not letting it flow, in case an ally accidentally places water and ruins the environment.

could be 2 option, fluid placement or fluid flow protection. I assume fluid placement is under block or item interact, so I guess it's mostly fluid flow that's a concern.

This is essentially just protection from bucket use, which is already possible. I think fluid flow protection could be incredibly bad for server performance.