To follow the thread of skepticism about the whole story: it's a bit like the customs entry form you have to fill when entering some countries. One question asks "Are you a member of a terrorist organization?". People laugh when they see this, and say "Why would any terrorist check 'yes' here?!". But the idea is, if they do catch a terrorist, if they can't satisfiably prove he's done anything wrong, they can still say "He lied while filling a customs form" and jail him.

So... maybe the company/boss has other issues with the guy, but no solid ground to fire him, until they caught him "violating" this "conflict of interest" rule.