First, torrenting isn't illegal, and No ISP "enforces no torrenting" lol
Your understanding of the solution here is a snake eating its own tail. Might wanna think on that one bud. Did the chicken or the egg come first? Solid Ratio or the private tracker account? Figure out how private trackers work first, then come correct.
The real answer here is that there are intro private trackers one can join on an invite or free join days. If one desires, one then works on their ratio there to get into a better private tracker.
Copyright holder's pay people to take snapshots of all the IP addresses currently leeching or seeding specific material on public trackers, so they can contact the ISP with the info and request they do something about it.