I don't think the cutoff is artificial. It comes down to conflicts of interest. If you give your friend a ride to the airport, he benefits, you choose to do it, and that’s the end of it. If you hire your friend preferentially, you’re compromising your duty to your superiors to hire the best candidate.

In your example, your CIO friend has a responsibility to the company to make the best acquisition on the best possible terms. If he’s treating you preferentially because you’re friends, he’s not doing that.