*ding ding dong* the next train to London Waterloo will now be arriving at platform one.
*ding ding dong* platform alteration, the next train to Waterloo will now be arriving at platform two
*ding ding dong* ignore that, it's platform one again
And so on and so forth!
This time next year, when millions of Olympics spectators will flood our public transport system, I predict we'll be spending half the day doing these kinds of things...