As a past National Ski Patrolman, I’ve had training in what to do about victims who have been knocked unconscious. The problem is that there may be no neurological or other symptoms for quite a while, and yet the trauma could have initiated either bleeding or brain tissue swelling which can progress to criticality at a highly variable rate. I believe the main problem with either bleeding or tissue swelling is that it restricts the blood flow to other parts of the brain, which then die.
Assuming there were no symptoms, which there apparently weren’t, shortly after Richardson’s fall, the important issue is what instructions were provide to her and the people with her.
Because it has been quite a while since I’ve had an update, I spent a little time reading some recent papers on “Mild Traumatic Brain Injury” (MTBI). The current “gold standard” for handling MTBI is a head CAT scan (hCT). However there are two problems, one is that there is no firm agreement that everyone who has been knocked unconscious needs an hCT, and when it is negative, it is by no means certain that a problem cannot develop. Also, even when the hCT shows evidence of injury, it is not always indicative of a critical situation.
So the key strategy, with or without an hCT, is to provide instructions to her companions that specify what to look for, and the urgency of action if any symptoms develop.
Back when I was a patrolman, CTs were not as common, and our instructions to victims who were apparently OK, and to their companions, were to observe closely for at least 48 hours, the occurrence of headaches, unequal pupils, confusion, and difficulties with speech, thinking, or movement.
I have not heard anything about what instructions were provided in Richardson’s case. If the EMTs (who arrived but were turned back) had access to the victim, it is possible they may have noticed something, but from the accounts have read, they probably would not have. However they might have provided better instructions that would have resulted in an earlier arrival at the hospital.