If it were me, I'd probably look at the various thresholds for "substantial wrongdoing" that the different theories of criminal law might support.
Is economic harm (e.g. shoplifting) a "substantial wrongdoing"? Arguably, it is a private matter between the shop and the thief.
Does "wrongdoing" include acts done to consenting parties (e.g. Brown as mentioned above)
Also, the inchoate offences issue, as mentioned by m'learned friend Mr Potato, is a good one.
Finally, "censure" implies that this is less about protecting the public, and more about discouraging bad behaviour. That could lead to an interesting line of argument over whether it is right to imprison individuals that don't pose any threat to the community.