What will happen when HQ airport of two alliance members merge?

[qunow]

So, there is an restriction for alliance members that each airport cannot be the base of more than one member airlines.
But what will happen when two airports merged to become one and both airports are headquarter of a member airlines of same alliance? For instance, if one airlines place its HQ at TXL and the other at SXL, what will happen when SXL & TXL close and BER open? Could they get the special treatment of co-basing in same airport?

[Sami]

Do not actually ever remember such case.. But has to be checked if such were to happen - case by case.

[schro]

I don't think there has been a case as alliance management should be responsible for making sure that a merged airport does not result in a co-basing violation. There's maybe a couple that would be desirable enough and that's about it, with dal/gsw moving to dfw being the main potential for grief.

So, to me, I don't think there should be a case by case exception granted - alliance managers should know better!