Your customers don't have to know about Asset Tags at all. Packages that support your package would have to. Your package could use them. If you don't need them, ignore the whole thing. Of course there must be a editable list of all defined Asset Tags for the project. People will use common reasoning and will not break your Tags. Why should they? Its like deleting a script and complaining that nothing works anymore. What can you do about that? As I said, this is a terrible idea. There is no uninstall system in Unity. If a user doesn't like your asset anymore, she just deletes your asset folder. Therefore having your stuff cluttering the whole project isn't a spectacular fun experience. People will start throwing things at you. And they are right.