All USPSA matches are tested and there are several hundred shooters. For example, testing is on stage 4. As shooters finish stage 3, they go test. It’s recorded. They go to stage 5. Match officials check PF for major and minor levels and if a shooter doesn’t meet, they face consequences.
Shooter gets to the test area, official asks for a magazine off the body and tests. May be first mag maybe third mag.
I prefer knockdowns that require a certain level of PF. Yes, it’s hard to keep them calibrated. Yes, it’s a lot of work for a match staff.