I brought this up to my brother-in-law and he pointed out that when Fred and George give Harry the map, they tell him that they have it memorized so they don’t really need it anymore. So it’s totally possible they just hadn’t looked at it since Ron had been at Hogwarts (and if they had looked at it, they were probably too busy looking at wherever they were trying to cause some trouble than at their brother’s dormitory).
I refuse to accept JKR plotholes.
(Source: ahlakes, via onthegraves)
