I disagree with a few points, especially the twanging of branches. If somebody in front holds the branch for you to pass, then OK, but if they are twanging them and not worrying about you, then you are simply too close to them. back off and leave some space. It's not that much fun to have a bergen in your face anyway!
As for power walkers in a group, I find it inconsiderate too. Unless something is decided from the start as to a fast, slow and intermediate group, then everybody should go at the slowest persons pace. Also, experienced people at map reading should be helping others and not just blazing a trail for everybody to follow. Pass the map around, point out where you are and where you want to go for the next 500 metres or kilometre and get the person to navigate to that point. Stick near them so that if they have any doubts you can give them a pointer.
I went up Wharncliff Crags with the Ratbag last weekend and a simple walk proved that my skills have faded a bit. I wasn't as quick with the map as I used to be. I suppose my last few years in the forces were in a vehicle, so map reading is a whole different skill on an armoured vehicle. You've all heard of the three norths; True, map and magnetic, well we had a fourth, tank north! This is where the compass points wherever it wants due to the mass of metal you are sat in!