I don't disagree on the more "subtle and nuanced" recruiting situations or that it can be a question of how deep one chooses to dig. Therein lies the tipping point though as digging requires resources and gaining additional resources is dependent upon what types of results they hope to achieve. If the results yield significant fines, impediments/deterrents to future wrongdoing or possible cooperation and information to more high value targets then they might dig, however, absent a very compelling reason to dig deeper they will at some point reach a point of diminishing returns.