In "professional" terms, the Issues of Ethics, RULE OUT, even the"Appearance" of bias, of corruption. of conflict of interest.
So therefore a Corporation, seating a board member, would seek to avoid the appearance of conflict of interest.
It is very basic, and very universal.
I don't know the facts, but Cheney, who had been a CEO at Halliburton, fought charges of conflict of interest, over sole-source contracts awards to Halliburton.
The left would cite this compaint, and the right would scoff at it.