You are right Ian.
But it's surprising that after explaining the pure water filtration and cleaning method to customers how many still make you the gracious offer..... "help yourself to any water you need from the outside tap."
It really does just go over the heads of people of what is involved.
Some believe that they can just go and buy a carwash brush on the end of a pole connect to a hosepipe and the outside tap and crack on.
And some people look at you as if you are trying to con them "Rogue Trader" style because you are not cleaning windows the proper way.
I have experienced all of the above scenarios, and in my experience only a small percentage of customers do not like wfp but most of them are not bothered and just want clean windows.