I have tested this on my own carpets, a polyprop to stairs and landing, cleaned and left for a few months and then cleaned and staingarded after, they definitley stayed cleaner with the staingard.
i did this just to prove something to myself, as i know polys cant absorb any staingard but in my opinion there still is a measure of protection form the staingard.
Has anyone else found this ?
Regards
Steve