Russell Beattie's whinge about US phone operators sitting back and letting you rack up huge bills reminded me that 02 actually looks out for you in exactly the way he's suggesting.
While in the US, I rack up huge (by my standards) bills and there's always a helpful little text halfway through the trip
This is a courtesy message from O2 informing you that your spend is now £50 over your line rental for this month. There is no need to for you to take any action.
How good is that?