Ah okay, fair enough. I didn't know that they were that demanding, assumed that they were allowed to be built because the server didn't struggle with it too badly. I'll just refrain from doing it all together probably,
I don't want to cause any lag or potentially crash the server. If I build part of my base with casts, I'll maybe ask an admin to overlook what I'm doing so they can tell me to stop before I go too far. Thank you very much for taking the time to reply.

Could we please get more clarity about where exactly lava casts will and won't get removed and update the server rules on the forums accordingly to avoid further confusion/misinformation?

I keep getting my lava casts removed because they're too close to spawn. Each time this happened, I asked the staff member involved how far away I need to make the next one for it to be allowed to stay. The first answer was the .survival range, I listened and made one outside that range just for it to get removed again. I later made one 5k blocks away thinking it would finally be far enough, that got removed too and now I get told it's .wild range I need to stay outside of. I'm honestly having trouble believing that doing it outside of any range is going to stop anyone from removing it, unless there's a clear server rule stating where it's allowed to stay.

If I make them at my own base, could those at least be allowed to stay? I know a lot of staff members think lava casts are ugly but I personally disagree and want to make them near/part of my own base. But right now I'm afraid of even doing that. Because if the wrong person sees a lot of cobblestone, they might delete my base.

Crazy build :o

My suggestion is quite simple, make one of the arenas (preferably the green one) a safe death at .pvp. I think it'll be a great way to draw players that would otherwise avoid pvp entirely out of fear of losing their items into that aspect of the game. What i've also seen quite a few players do already, is going into a match under the agreement that afterwards items get given back. Basically creating exactly this safe death scenario but ultimately leaving it up to their opponent to decide if they follow through with the agreement.
Overall just seems to me like it would be a great addition, the demand is obviously there. I also think it will bring more activity to the regular arenas after people have practiced and grown more confident in their skills.