its daft, but its the channel with "1" in it, so it must be the flagship channel.
the link above mentions ratings chasing. it seems eqully daft that people will simply have BBC1 (or ITV1) by default and therefore whatever is there gets higher audience figures.
you'd think so. but its not a new thing, its always happened, its a prestige thing to have coverage on BBC1 and they like to put the few event that they have there.