Hermione's greatest fear

[its_a_monstertrucker]

No: HPFGUIDX 87450

I think it's implausible that Hermione, even in PoA, could imagine 
nothing scarier than failing classes.  Most likely she made up a 
lie about the boggart being McG, because she was too 
embarrassed to admit what her boggart really looked like.  
Perhaps we'll find out her greatest fear in book 6 or 7.

As for whether Lupin knew, I doubt it.  Is there any other evidence 
to suggest that he's a legilimens?