added simple protection check

api.lua

@@ -191,3 +191,12 @@ function pvp_block.register_on_punchplayer(player, hitter, time_from_last_punch,
 end
 
 minetest.register_on_punchplayer(pvp_block.register_on_punchplayer)
+
+-- protection
+local old_is_protected = minetest.is_protected
+function minetest.is_protected(pos, name)
+	if pvp_block:in_area(pos) then
+		return true
+	end
+	return old_is_protected(pos, name)
+end