Can the Marauder's Map be deceived?

[Liz Muir]

No: HPFGUIDX 54202

--- In HPforGrownups at yahoogroups.com, "Devika" <devika at s...> wrote:
Briony Coote wrote: 

>>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? <<

Devika wrote:
>>My theory is that the Map only shows people who are relevant to  
the "mischief maker" using it.  IIRC, when Harry uses the Map, it  
usually shows Filch, Peeves, Dumbledore, and others who might make it 
difficult for Harry to sneak around the castle.  The map never seems  
to show all of the students in the school (at least, we aren't told  
that it does).  This is probably because Harry really doesn't need to 
know that there are students in Gryffindor Tower or in other common  
rooms, for example.  The Map only shows the people who are near to  
Harry or who might affect where he is trying to go.  When Fred and  
George used the Map, they probably did not need to know about Ron 
and  where he was or about people in Gryffindor Tower.  Since 
Scabbers was probably in Gryffindor Tower when he wasn't with Ron, 
there would be  no reason for him to show up on the Map. << 

My personal conviction is that the Map has a sort of built 
in "confidentiality clause." If you don't know who someone really is, 
then they would appear on the map as whoever you thought them to be. 
Thus Scabbers would appear as Scabbers. (If you are familiar with 
Diane Duane's _Young Wizards_ series, this concept is similar to the 
one presented in _A Wizard Abroad_. The one about why the Manual 
didn't list Nita's aunt in the directory.) 

However, this doesn't apply to strangers. Since you haven't mistaken 
their identity, they will show up as their true selves.

Rowen Avalon, who remains amazed that there is still so much 
discussion on this list, since we haven't had major additions to 
cannon for 2-3 years!