I have no problem with well behaved dogs being on buses or trains, or dogs in general. However they certainly shouldn't be on seats.

I travelled into London in mid afternoon the other day from HOP. The train was 2 carriages. Right in the middle group of 3 facing seats of one carriage sat a dog owner in the window seat with his/her (couldn't tell from behind) feet on the opposite seat (!) and the dog sat on the middle opposite seat. I am of course sure the dog would have had a ticket (yeah right!).

The dog didn't look aggressive, but nobody attempted to sit beside it, even though the train got quite busy. Being British none of us said a word, we just tutted under our breaths.