Truth is, pair programming is one of the only effective ways that a lot of us have ever witnessed keeping average developers from pissing away 95% of their productivity engaging in non-work such as reading and writing blogs, instant messaging, personal email, shopping online and otherwise wasting time on bullshit.
So, we need the XP youth to keep us inline? If I'm not doing my job, I should be fired. Period. End of story. We all can't be above average, but we all need mental breaks (I doubt most developers spend 95% of their time shopping online).
Pair programming has pluses and minuses. It takes a certain personality to be good at it. I've had very few good pairs in my career. Nothing can match the creativity of two minds locked in a common crusade. It's great. BUT, I have found it takes a person that can take constructive critism of their ideas, is vocal, loves programming, and the most important: listens. Your average developer if he's browsing the net for 95% of his time probably doens't "love" what he/she is doing. I found while pairing can give the illusion of productivity, it's easy for one part of pair to be asleep at the wheel to speak. If you don't love what you do, you will find ways to avoid doing it no matter what hurdles managers throw at you.
I love pairing with passionate yet humble programmers (the greatest minds I have met have been this way). But, I hate pairing with ego maniacs. I love short bursts where we colloborate intensely and then go program solo for a short while. Get back together and show each other what we did. Rinse, repeat. I find it keeps the creativity spark alive (because you can experiment without the sucritiny of another to verify if the idea is good) and the interaction rich. It allows the feeling of working together, as well as ownership of a piece of it.
Pairing should be something that is not mandatory. It should be up to the programmers. Anything forced is going to cause people to find ways around your dogmatic rules. It's human nature. XP should be agreed upon, not enforced.