I have no problem with seeing people in uniform anywhere.
However, do these guys actually _want_ to travel in their uniforms? Unless it's a hassel factor to actually change into civvies, I would have thought they could'nt wait to leave the uniform behind for a while.
I also can't help wondering what all the post would be if they reversed the order and stated that all service personnel MUST wear uniform when travelling whatever the mode and means of transport.