As unimaginable as it might be to legalistic, individual-oriented societies of the first world, I have witnessed the cultural-transmission of treachery from parent to child and from teacher to student by the authority figures conveying this behaviour as socially-acceptable, or even the right thing to do. I have heard a teacher tell a student to raise the prices for farangs (foreigners, a.k.a. "Walking ATMs") of her wares at a student crafts-sale, as if it were the only reasonable thing one could hope to do. This particular example was in Thailand (note: collectivist society, meaning you can have a level of certainty that the majority of people from that society - who tend to speak about themselves in the plural - will have a degree of shared values that is unchanging from one person to another.
Nigeria may not be collectivist as Thailand, but I don't see why the transmission of values described above couldn't happen in there, too.