Appropriate punishment
So what would be the right course of action? Philosophically, zone infringements are a safety issue not a criminal law issue. For well-documented reasons, in most of the Western world we don't normally prosecute professional pilots (or controllers) that make errors. If someone is genuinely criminally negligent then there are appropriate mechanisms - pretty damn rare though.
We should apply the same rules to PPLs. If it's criminal negligence then we should punish appropriately, if a well-intentioned pilot - perhaps low-time, perhaps just unlucky - screws up then we need a programme to make him/her less likely to do that in future.