I would think that any business would have an expectation that their employee act in a professional and responsible manner and not like an idiot DYKWIA. Although my company has not stated it directly, I have always believed that when I am traveling on the company's dime, I should am expected to behave as a representative of the company.

Therefore, this issue should never come up and there is no reason to ban a specific airline other than for legal reasons.

Infact, our policy is to chose the cheapest airline. However, I'm able to book mostly UA by choice. I find it amusing that people think that switching to another airline will be any different.