But you're suggesting browsing is a definitive method to achieve or research an issue. The problem is browsing is not a reliable tool. One minute I can't browse someone, 10 mins later I can. Perhaps initially with zero files, but then with 50 & later with over 1,000 files. Or other way around. One minute I browse them & they show 4 star connection quality, 15 mins later they show one or 2 star.

So if you're using browsing to determine who is a freeloader, that's a very poor & ineffective & inaccurate method. Browsing can be affected by how many upload & downld slots & bandwidth both you & them have, & whether perhaps they have chat enabled (which tends to make it easier to browse), etc. I might be affected by local traffic or traffic somewhere else between you & them.

I'm not sure what you mean by dynamic ip filtering, since their ip's can change every few days or so. So how to keep track of their new ip's, etc.