This is a new one for me. I thought that I had heard it all. Now I'd expect something this from Berks county PA tightwad Dutchmen (PA Deutsch, actually). I've actually heard of some pouring weakly brewed coffee back into the clean water tank on a Mr. Coffee to stretch the coffee (never figuring out the fouling of the element and the added electrical cost of doing it). There, being cheap is not just a cultural madate ..it's a refined art.
...but to actually go to all the trouble to remove a fitler and clean it ..when a $2-$3 item can be had anywhere, not to mention intentionally adding fuel to the sump with residuals, sets a whole new benchmark in cutting corners and ignorantly paying for it.