No, you said func_detail is an entity, but it's not. Func_detail is not an entity in any way... Oh, before I forget, this is how I define an entity:
"A defined c++ clas linked to an in-game existing object with a classname."
No entity will seal a level. Only world brushes will do that.And yet, someone said it doesn't count towards entity limit:
It doesn't clip surrounding brushes, doesn't count towards the entity limit (func_wall does) and still casts shadows (func_wall doesn't).And since it only exist with ZHLT or any tools built on that technology (VHLT), it doesn't exist as an entity in-game.