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Put it in a contract or in a sheet that you hand to each customer "What to expect" and then they can't mess with you. After dealing with a few like that myself, a few months ago I did this and it's kind of laid out like this:

*Logo*
*Address*

"Our Responsibilities"

"Customer Responsibilities"

"What to Expect"

Obviously there is more to it than that, but they see what we are going to do, they see what they need to do (turn water on, close windows, move cars, move sensitive and fragile items from where we are cleaning, etc). It also allows us to lay out our expectations of what will happen with their property, in the case of chalky vinyl, they are already forewarned that their vinyl siding has seen better days and while it is going to be clean, it may have an uneven appearance in certain areas where it is oxidizing.