What Leungbok said.

There are no cheaters on the rankings site as it is more a reference for top pilots and in a way more for yourself to see what the best times are. If an unknown person suddenly puts in a Top3 time then questions might be asked but usually new pilots come on and put good times and then improve those as they become better and well known. Those with World Records and lots of top5 times will no doubt have a few videos here and there and also you will meet them online and it will be pretty clear that they are very fast.

Hope that helps. Keep using the site - it is far more accurate and populated compared to the out of date online leader boards!