First, I have no inside info on why he was there.
But, if he was there because he was present at previous proceedings (merger negotiations) that are of importance to this arbitration, why not. What, you don't like it because he may actually curtail some free wheeling spin of the truth (lying) by the Polar MEC at this and other proceedings? If he's there to maintain some semblance of truth, bravo.
BTW, Atlas/Polar is just a wee bit different that your FedEx/Delta example, but don't let that stop the spin......