The problem, of course, is that redbeard is likely not the only person in his/her company who travels. And those who do travel regularly would, understandably enough, want to book flights on the airline that has the better service and provides the most FF benefits, not necessarily in that order.

And so the $600 difference in fares, when multiplied by dozens or hundreds of trips by dozen or hundreds of employees, gets to be serious money. And managers, who are generally evaluated on whether or not they've delivered what they're supposed to have done within their allotted budget, are doing what they're supposed to when questioning, and often refusing, requests such as redbeard's.

Every case is different -- some travel is billed to the client and other travel is paid for by the employer, for example. My company has what seems to be a reasonable policy: I have to book through our travel agent, I am requested to book the lowest fare, but I may (at my option) book any fare within $100 of the lowest fare. (Exceptions are routinely granted if the lowest fare requires more than 1 plane change, etc.; otherwise, exceptions are possible but generally hard to come by.)