I would tip. (full disclosure, I was a professional waitress for a looong time, so am pro-tipping in general) With that said, when it comes to my pet's care, ie grooming, etc- I always tip for a couple of reasons: these aren't typically high paying jobs- the people that do them are usually there because they love the animals, not for big bucks. Secondly, and more important to me, assuming I am happy with the service, I will be back... I want that person to remember me as the customer that tipped them nicely and that gives me better odds at getting better service the next time around. I always remembered customers that tipped me well, and they got preferential treatment, and I'm sure that goes for all tipped employees. I'd give 10- 15% percent depending on how you feel about the experience. Enjoy your trip :)