Con artists count on personnel being too harried - or greedy - to notice their devious intent.
Several years ago I got a letter from a Nigerian "prince" inviting our company to participate in an exciting business proposition. He and his cohorts had millions of dollars they wanted to deposit in the US, but because of legal technicalities weren't able to do so. Desperate for a partner, they would gladly cut our company in on a sizable fraction of their loot, if we would give them access to our bank account so they could deposit the money.