Originally Posted by
L.C.Why
The high priority refers to the message not the passenger.
This is also what I've noticed, having a peek at the screen on certain occasions during check-in. Sometimes it's related to a document check, some other times another message to the gate agent (recently, I can't remember if on BA or another airline, they were advising me that I wouldn't get a meal due to a last minute booking, and stuff like this...).