Yea, if you have notes with the same name, but if you want to just reference the name, it will be a problem. Also, this also means that you only have one userstyle.css note for all clients, otherwise you would have to reference the id and not the name. IMO this is too fragile.
I'm strongly against creating folders for users. Remember the welcome notes and notebook mess, which btw still screws up people's installations? At least the tags are gone for the welcome notes now.