Warren Buffett is not directing resources from his position in one company to enrich himself in another company that he may have large personal holdings. That is one of the few ways shareholders can get around the safety of a corporation and sue a shareholder.

More to the point, the board of directors are going to be extremely interested in the actions of Buffett if they think he is trying to enrich himself at the cost to their company.

Using him as an example that is.