There are also reputational risks at stake for management - i.e. directorships, working together down the road etc.
If the directors have in fact accepted the revised DLS unconditionally (i.e. not pending a higher offer from Magnum) then I find this unethical as they are essentially trying to block a higher Magnum offer (because DLS will now have an even larger chunk of AQO). This directly disadvantages the rest of the uncommitted shareholders whom these directors are meant to be representing. If DLS had only 20%, then Magnum might be more likely to put in a higher bid, perhaps for cash. I am surprised directors are allowed to do such a thing when they've been paid fees for so long to represent shareholders interests. Why didn't they simply say, we will accept the offer conditional on no higher offer from Magnum?