I too am curious about this. I have not been doing this and sometimes when rolling the front windows down I get a pretty bad squeak. I don't know if it is from build up on the window that I haven't gotten off while washing, or dried rubber seals. Maybe the silicone spray would help. I don't know if that would have negative long term affects on the rubber though. It seems to be coming from the vertical rubber seal where the mirrors are on the A-pillar.