All of my outdoor clothes have at least mud on them, all jackets have treats/biscuits/poo bags in them, car has blankets and spare lead ropes in them and a bowl and water.
I was on the train to Olympia and a few seats away was a very cute well behaved Kelpie X Collie who was on her way to Olympia to do the agility - she came to say hello and I was talking to her owner - little dog was very interested in my right pocket (jumping up and nudging with her nose etc - owner very embarrassed until I realised I had some of Max's treats in there!! Shared them with her for a demonstration of speedy sit and down!!