The common negative response to pair programing from management is “I can’t afford to use two people to do one persons job” . As developers our common reaction to this is to explain how pairing can be faster, result in less bugs etc. This is understandable as these are the benefits most obvious to developer. But I would argue that it is business continuity that could be the killer argument for pairing.
Quality isn't the only reason for pairing, as Dave Hownslow points out at Think Foo. Building software as a team is important, and will generate better results if done properly. Being the "Lone Wolf" developer is no longer a real option if you're working as part of an agile team.