OP
One_of_them
I agree with what you all say however as you all know the only thing people care about is saving money. Therefore you could go out to quote and if they mention running in cables themselves, take another hr or so explaining exactly where you want stuff, that you want to see ALL cables runs so no plastering or refitting floors until all has been checked. Budget this extra time and inconvenience into your quote anyway. And then firmly explain that if they do not follow your exact instructions you will not continue the work and nor will probably anybody else?