I just picked up a 15" surface cleaner for my Honda pressure washer and I got to say it sure makes a difference. I got my suegra and two of her neighbors lined up for this weekend. Watching yours and a couple of other RU-vidrs videos inspired me to give this a shot. A little extra cash on the side is a win win.
I'm glad you guys got the work, but feel bad for you knowing that the second the job is done, that dog is gonna go back and poo there again and wreck your good work.
I honestly think it would be wise to label your work in such a way it does not offend current or future customers. Nice work in cleaning things up. Everyone can use some help with problems or a boost to give hope.