I think DM and EE would only be brought in towards then end of any negotiations to anoint a draft deal so that might explain their ability to participate in PP's and trades.

I generally thought the same thing as you but... isn't the very knowledge that the CEO/CFO is in negotiations enough to black them out be considered insider trading? I mean if it's confidential enough to not tell us, than it should be confidential enough to not be able to trade with that knowledge in hand, no?