This response feels knee jerk. It's been demonstrated in countless other threads (1) and articles (2) how economically important it is to overbook. Overbooking is central to airline profitability and their ability to provide flexibility - like partial refunds, or SW's "open tickets" policy on business select. As a consumer I appreciate these things and find them incredibly useful. United's response of "We'll push the…
Edit: An exception may be Easyjet (though I've never seen it happen and I fly them a lot). They offer flex tickets mainly aimed at business flyers which would make it worthwhile for them to do some limited overbooking.