Not everybody plays dungeon crawls. Plus not every group has somebody in heavy armour. I suspect that in general the less you play crawls the less likely your group is to scout.
Plus at least one of my groups decided that sending a about was stupid, because they'd get mulches by the enemies and we'd still be going in blind. Plus you know, the loudest assist of the party was three of us wearing black trenchcoats in modern day London.