I wonder actually though if it was more of:
“hey, you are welcome to go to the start” warmup volunteer tells her. Or “we are running ahead, you will be able to go 10 minutes early if you want”
She thinks okay, sweet I can start early, let me get 1-2 last warmup jumps in and I’ll head over
She heads over a couple minutes early
Starter says no, you can’t go until your start time, this break was built into the schedule to allow [restroom break, volunteer change, score pick up, etc], so you still have 9 minutes before I can let you out of the start box
So then she has to return to the warmup, get her horse ready to go out again & then may end up rushed to start. She can’t keep his blood up for 9 minutes waiting for her start time so she has to let him relax and then try to get his blood back up again.
This was my understanding based on the information that grumpy man gave. So not that she wasn’t allowed to wait until her ride time, but instead wasn’t allowed to go early even though there was a gap in the schedule.