> 
> "How did you know it was me?"
> 
> 
> 

This is what Minerva says when Dumbledore reveals that he knows she was there... 

> 
> "Fancy seeing you here, Professor McGonagall." … She looked distinctly ruffled.
> 
> 
> 

She shouldn't have been so surprised if she was registered, now would she?

Yes, I know she was registered when Hermione checked, but that was a decade later.

**Was Minerva McGonagall an unregistered animagus in *1981*?**