[HPforGrownups] Can the Marauder's Map be deceived?

[Troels Forchhammer]

No: HPFGUIDX 54193

At 10:07 24-03-03 +1200, Briony Coote <briony_coote at hotmail.com> wrote:
>I have three questions about the Marauder's Map:
>
>1 - Why didn't Peter Pettigrew show on the Map during the years that the
>Weasley twins used it, or when Harry started using it?

That is not explained. Theories include the possibility that he actually 
did appear, but no one noticed it, or that the map shows only some people 
(how it would decide which people to show is a separate question in its own 
right ;-) - and other ideas that I can't remember right now.

>2- In GoF, why did Barty Crouch Jnr show as "Barty Crouch" and not
>"Barty Crouch Jnr"?

Because his name was Bartemius Crouch - the 'junior' is just tagged on to 
distinguish him from his father.

>3 - Why did Barty Crouch suddenly disappear off the map when he was
>right there in Snape's office, disguised as Moody?

He didn't disappear as far as I read the book. Harry never gets to look 
properly at the Map again after seeing 'Crouch' in Snape's office.

Troels