First shoot around here starts Monday (grouse) and anyone turning up in trainers and trackies would be left behind. I would like to see how long your mates trackies would last beating around here. I would give him an hour before he was torn to shreds, soaking wet, cold and wanting to go home, and that is why you dont wear trackies, trainers ect ect when out beating. Fashion has nothing to do with it.
As for speeding up on his bike when seeing horseriders, he would only do it once around me and he would be getting backfilled in on the next dig I was on. He sounds like a first class pric*