Address it to DB, and include OH as a courtesy if you have any relationship with him.
It comes down to decision theory, Choicechoice under uncertainty.
The simple matrix is below:
The consequences of including OH is that at the very worst, he will be mildly unhappy. But, if you excludingexclude him, and he's likely to be upset, he will be VERY upset.
Logically, you should include him, as the risk is minimal.