Adverse issues (e.g., fraud) tend to get noticed more in downturns, because, generally, everyone cares more about the details in those times. In times of plenty, they also occur (perhaps even as much), but people are more willing to let the same behavior pass because everything is going well.

At the risk of stepping too much into the meta, I wouldn't be surprised if there are some innate behaviors from evolution for responding to downturns (e.g., caring more about fairness).