Reuters has crunched some numbers, and come up with one way to measure just how aggressive the Saints defense was in 2011, a year played under their bounty system. By taking the number of total penalties and identifying the percentage of "violent penalties"—that is, unnecessary roughness, chop blocks, late hits; etc—they determined that New Orleans was the biggest offender in the league.
A whopping 37 percent of flags on the Saints were for safety-related penalties. To put it in perspective, the Raiders, the most penalized team overall, only scored 20 percent. The Saints also led the league with 1.6 "violent penalties" per 100 players, nearly twice as much as the league average of 0.84.
It's not a perfect metric, and it doesn't prove anything—a late hit can be the result of sloppy play just like a false start—but you better believe if the Saints weren't leading the pack, they'd be using that info in their defense.