I will say this, just for what it is worth. IME it is not uncommon for volunteers at warm-up rings to be given important instructions, but to not know how things work. Of course that can vary depending on the venue, the volunteer, and who is coordinating volunteers with little or no experience.
I’ve seen riders sent too early from warm-up to do their dressage test or XC/SJ round. That seems to be a common error. The inexperienced volunteer is in an important role but doesn’t know the ride time rules. And IMO it is the fault of whoever should be coordinating the information that volunteers need to do the job.
When that happens, a rider can normally point this out and be allowed to stay in warm-up until their ride time (that’s a rule, too, of course). I’ve been in that position myself.
A volunteer may have just put their name in to be helpful, knowing little or nothing about the sport, and is handed a clipboard with very brief instructions. Along with the admonition that a primary mission is to get riders to the in-gate (as it were) as promptly as possible. The volunteer is inclined to take that admonition seriously as having been given authority over this task, and given to understand that this is what the event needs from them.
While having never been informed about the ride time rules. They may have the ride times, but not know the rules, and think that the competitors move on one after the other as they might have experienced with other sports. This volunteer situation is so common, IME. It is why the USEA has some videos on how to do volunteer jobs, that volunteers can watch in the days before the event. Assuming the videos are still up on the website.
When the rider is questioning the volunteer, then it is up to everyone to have been informed as to what to do when a question comes up, who to call for help and information. And that official needs to be available on the radio promptly, because so often time is of the essence. When that process doesn’t happen is when things can get sticky for the rider and the volunteer.
I have no idea if that is what happened in LN’s situation. But it is easy to imagine given what has been described in this thread.