On the few occasions I've finished work on a Sunday night at 2200 then tried to use I Player to watch Top Gear I constantly got some message about " insufficient bandwidth - please try later"
And they seriously want me to pay for this service - they're having a laugh. It's quicker for me to download the program illegally from the net than wait on I Player!
PPV is not the delivery model for future mass market TV. Time and time again in the TV, broadband, and other entertainment markets, consumers have shown that they want to pay a fixed fee for unlimited usage.