I think you need to learn how to understand what you read. I am arguing that chronoing has serious flaws to the point where it is more of a ritual than a useful process and that sites should not rely on it to ensure that all guns are within limits when in play. 99% of sites are wrong. I am NOT arguing that trust is a valid safety check either. Proactive monitoring with permanent bans for transgressors would probably be more effective.
Just as an example of why chronoing is not a reliable process, a while ago I went to a site that has a limit of 1.13J for full auto capable weapons. As usual, I had two rifles with me; the first one chrono'd at 1.08J, the second at 1.15J. My response to the second one was "Oh shit! I won't be using that one then. No problem" or similar words. The chrono marshal just put a tag on it and said "No, mate; you're good to go with that." I didn't use it.
When we had airsoft insurance it did NOT require us to chrono every gun at every event. I cannot remember the exact wording, but it required chronoing of guns that were new to the site or which had been worked on since last being at the site, which again relies on players to be honest. I know that condition was not unusual as I asked site owners if it was the same as theirs.
My friend was giving an opinion based on his years of experience of how negligence cases tend to go if they get to court.