If they aren't using RTB (for auto installing), I predict that some people will attempt to extract the files or place the .zip files in the Blockland folder. (Then have the Add-On not actually run)
Actually, wouldn't extracting it so you get Add-Ons/Weapon_Whatever/Files work just as well as having Add-Ons/Weapon_Whatever.zip/Files? Blockland doesn't recognise a difference, so...