I went to green industry trade fair last month and spotted a Swiss made anti-cobweb product called "Adesectin".
Grass growth has been pretty sad down here of late. So I have been offering Adesectin as part of a pressure clean. It's long lasting (I guarantee effectiveness for 3 months) non-toxic, orderless, colorless agent. It is harmless to humans and animals. It forms an invisible, crystalline film on treated surfaces that stops webs from appearing for at least 3 to 6 months it holds properties as a contact insecticide and an oral uptake toxin against mosquito's, spiders, cockroaches, ants, silver fish, mites, flies and wasps. Its great stuff!. I have been asked to treat a few clients boats and inside their houses, this is just really nice as a change. I don't know about availability in the states but this is worth finding out about!
MMM, I pressure wash a very high ceiling quarterly that is all cobwebs. Perhaps if I applied this stuff I can focus on cleaning the rest of the building and cut my time in half. So,it works like you say?