The summer heat and working dogs

I know you are NOT supposed to touch, pet or otherwise interfere with a seeing eye dog while his/her harness is attached. What about offering the owner water for the dog? I was on the train the other day and a woman entered with her dog. The dog did not seem to want to sit/lay down (actually, I wouldn't want to touch the floor of an L train either) but when it finally lay down, it was obvious the dog was hot. It was panting frantically. I had an empty container after bringing a salad to work and a bottle of water in my bag. I was across the aisle so I could not lean in and ask. Was I wrong to not ask her if she would have liked a bowl of water for her dog? When I exited the train, I encountered a man waiting at the bus stop with his dog. Should I have stopped and offered his dog a drink? I don't know what the protocol is and I did not want to offend anyone, but it was hotter the hell outside and the dogs just seemed to want or need a drink.