It's more about process than value.
Companies are audited by both independent auditors and tax inspectors and I know from experience that they'd rather do something "regular" that costs more, than something "irregular" that will draw the auditors' attention.
This is also the case with clients if the flights are being charged on to them - a destination that is not in the agreed routes will set alarm bells ringing.
By and large, I let my service people do stuff like this if it won't cause too much hassle but often employees with great cost saving ideas (that also happen to benefit them!) don't take all the backroom costs and hassles into account, or they underestimate them.