I also use wfp as well as ladders.
I didn't bother telling any of my customers about spotting or runs. I thought if i told them about it they will start looking to close once i had finished.
Some took some convincing about leaving the windows wet, but i told them i would come back and do them again if there were any probs.
I noticed some spotting when i first started using wfp but left it to see what people would say. They were only small spots and you couldn't really see them unless you went really close up.
No one said a thing when i went back to collect my money. If anything they couldn't believe how clean the windows looked.
I tell all my new customers now about the pole but never about spotting or runs.
Now i seem to have the hang of wfp i don't bother looking anymore. I think it's just down to confidence.
Craig