Marauder's map question, prior to PoA

[pippin_999]

No: HPFGUIDX 191957


Robyn:
> Hi,
> Why didn't Fred and George ever notice Peter Pettigrew on the Marauder's map prior to PoA?  Why would they not have noticed that someone named Pettigrew was very often in the same place as their brother Ron, or at least, that someone they didn't know was hanging out in the Gryffindor common room and dormitories? I have looked at the FAQs on this topic, and feel like there must be more to this ... is this a hole in the plot?

Pippin:
The problem is partly JKR's maddening inconsistency about the number of students. If there are (as is sometimes implied) really about three to four times as many students in Harry's year as the forty that JKR created, then it's not surprising that the Twins wouldn't know them all. And while everyone seems to know that Sirius Black killed twelve Muggles and a wizard, few seem to remember who that wizard was. 

But it also has to do with the way that the Twins used the map, IMO.  Someone like Percy or Riddle, who was  interested to see who else might be rule-breaking, would have spotted Peter in Harry's room when everyone should have been at class. But the twins aren't interested in busting rule-breakers or blackmailing them. They would have used the Map the way Harry did, to keep out of the way of Filch, Mrs. Norris and others on the prowl for rule-breakers. Students asleep in their beds were of no interest to them. Also, as they told Harry, they didn't even use the map much any more. They knew where the secret passages were, and  their knowledge of magic had advanced enough, as we see, that they had no problems avoiding teachers and such even without the map. 

Pippin