According to Andy Reid's press statement after the game, the players are the ones that asked for the red pants, Reid in turn asked Dorsey, who in turn got the okay from Clark Hunt.
JMHO, but I think it was more of personal statement from the players than anything. And if it makes the players feel more confident, so be it, let 'em. Judging by the way they played, they earned it.
On to Philly.