I like your suggestion. With the introduction of the Driving Academy we have the best means yet to sort out mean-spirited players.
However, it is not taking into account that a great number of trolls don't wait for their ban to expire before rejoining the servers.
They have countless game keys in their drawers waiting to be used to evade any ban. Additionally, we'd still have to deal with any and all first-time offenders.
So, I feel that an even better way to create a roadblock for trolls lies in
making the successful completion of the Driving Academy a requirement for ALL accounts
before joining a server. Just like when a new set of rules gets passed and the system checks whether the user has read (scrolled through...) the rules,
the system could implement a check for the Steam achievement "Dedicated Student" or whichever more challenging (and time-consuming) achievement will be introduced for future
chapters of the Driving Academy.
For, let's be honest: the trolls lack both skill and patience, and making those a requirement could really deter them from wanting to engage in their malicious activities in this game.
They will just look for an easier game with no entry requirements.
Also, I don't think it would be quite possible to implement different requirements for playing for different groups of users (no Driving Academy required for players in good standing,
Driving Academy for banned players). I think for various reasons (practicability, transparency, equality, etc.) the requirement should be identical for ALL users.