Hi radarman,
Just how do those fire chiefs access POB information from an airline manifest in a timely fashion? Where we are, they'd have to wait a day or two to find a telephone number for the airline, let alone the numbers on board.
Seems to me that it's a much safer method passing on your POB info on start up or on first contact with TWR on arrival so that, if there is an emergency, you don't have to ask an already stressed pilot questions that he'd rather not answer with the increased workload.
And riverboat, it's precisely because of the possibility of an emergency that we obtain POB info before the fact, according to the training I received back in the dinosaur age.
Bottom line; I'll happily take your POB when you start or on final for your arrival runway. Yes, it may not always be completely accurate, but it's a good starting point.