I feel patronised by yearly mandatory training. All of it seems obvious and not relevant to me because I’ve never negotiated a contract on behalf of my employer. Still, good to know there’s plenty of people who might find training useful.

It's also for everyone not involved to notice something is wrong if they overhear a contract-related conversation that mentions kickbacks.

s/understand/care

Perhaps I'm naive, but I think the number of people who know and don't care is a small fraction of the people who honestly don't understand that they're doing something wrong. I mean, obviously this guy knew he was doing something wrong, but a lot of people just can't imagine that their own unethical behavior wouldn't be obvious to them.

I think a lot of people feel "clever" and like what they're doing is, while not expressly allowed, not forbidden either.

See a bunch of people in this thread finding out they're probably committing tax fraud by underpaying themselves from their own s-corp to dodge taxes.

Haha I do taxes for a living, and the number of times people have said, "My buddy does this and he says it's fine." As if the fact that the person hasn't been caught is evidence that what they're doing is legal. It's what you mentioned, they feel clever and don't think they're doing anything illegal.