[ASA] - Rules for PvP Cave entrance and building?

[DTM]

I'm curious to know what ya'll are doing for rules when it comes to PvP Cave building. We have a rule that you can build in caves but cannot directly block the spawning of artifacts/loot drops. I know some people like to block the cave entrance and I think that it's fine if it's not a cave with an artifacts/loot drop but if it is we'd want to keep that open, however, I know some players that join would argue that point that it limits the area that you can build and defenses which I get so I'm looking to know what everyone else is doing around this topic. The goal here is to provide a balanced fair PvP experience (as much as possible anyway)