Boring but true answer - the lawyers will have insisted the didn't talk about it.
I previously got acquired by IBM and was at a similar dead duck Red Hat event before the deal closed as an IBM speaker.... There will have been N layers of legal review of every speaker for that event - IBM have had previous issues for asserting undue control before the deal closed and so any event pre-close is micro-managed within an inch of its life. Trust me, the speakers all knew it was the elephant in the room, some of them may have even suggested addressing in, and gotten a legal going over they won't forget!