A lot of lifters, no matter how good have never been taught to brace correctly, and there is no shortage of ladies in the sport with pelvic floor issues who have problems with leakage, however I have not met any personally who pop tampons and I think I have only ever encountered one on a ladies lifting forum who has had that problem. I have a small amount of pelvic floor weakness in everyday life after 4 kids but it has never been a problem on the lifting platform when concentrating on maintaining that tightness, which is needed for safe lifting.
As a sport, many powerlifters are self taught by watching videos, or have only had a regular personal trainer to teach the basics, I don't know what it is like in some other countries but personal trainers are not always well trained, I have lost count of how many personal trainers I have seen tell their clients to tighten their core but not actually be able to give any cues for the person to be able to actually achieve core tightness.