Your whole post boils down to one single point: "if it addresses these attitudes [...] ‘pour encourager les autres’"
If you're not aware, the origin of that comment was in Voltaire's Candide and was in reference to the execution of Admiral John Byng for failing to relieve the beseiged British Garrison at Minorca
Byng was effectively made a scape-goat for the British Government and Admiralty's failure to do *their* job properly by a) not acting in time to deal with the expected French attack on Minorca and b) sending Byng out with ships that were undermanned and in a poor state of repair.
So you're looking to do pretty much the same, find a scapegoat to blame for *your* failures and if that requires locking them up for four years, well, that's not your problem, is it?
The fact that "make an example of them" sentences have been shown throughout history to be abject failures in dealing with the root causes of problems seems to be of no concern to you either.