The checks for whether something is an FLE2 state collection are just based on the namespace. However, it is possible for a user to create a normal collection (not involved in FLE) following that naming convention. If a user does this, any checks for that collection being an FLE2 state collection will pass, which can cause weird behavior. For example, we will not allow the user to call moveCollection on that collection because we expect it to be an FLE2 state collection and we do not allow tracking those collections.