This is really small "problem" but i don't see that this notification is usefull to anyone. But if you play browser/mobile and late register for example, it is kind of annoying that when return to lobby, you get this notification. I know i am registered when i have been on table . And even pre-reg it is useless too. You can see register button turn to unregister. If you want to make it more obvious, turn reg button different colour when you are registered vs not.
Again, not a big thing but when you are trying to play multiple tables at one time, every unnecessary click is bit annoying.
And pliis bring that check/fold button too. Another useless click if i will fold no matter what