The proper way to cheat is to not leave a trace on the tracker where a tracker staff may or may not make correct judgement. It's called "ghost leeching." Basically you directly connect to known peers' IPs (e.g. from some heavy seedbox users) and never even report anything back to the tracker.

Of course, those peers where you ghost leech of then would correctly report the upload they generate (making THEM look suspicious of cheating by "over-reporting" upload.) It's impossible for any tracker staff to properly detect and attribute proper cheating in such cases, unless they can detect a pattern. The tracker staff objectively can only catch people that do really stupid things.

That's just the way BitTorrent and private tracker economics work. A "private" tracker is more like a social contract between its users to do the honourable thing, but you'll always have some idiots that do not get that, of course.