Despite being someone with close to a pathological hatred of shorts, I can confirm that I have never felt the need to flee a train, station, or railway property because of the presence of a member of staff's legs. No comment on the "outfits" preferred in this heat by some of the passengers, however...
At least GWR's IET shorts policy gave me a good laugh. It's not even as if it sounds great in theory! As long as the member of staff is helpful, I really couldn't care less what they were wearing. I've seen drivers with all kinds of interesting headwear, and it doesn't seem to affect them, so why would a guard wearing shorts on an IET cause the world to grind to a halt? Top marks to "Bob" for his act of protest as well.