Learning by numbers
The knowledge required at PPL level is BASIC and it needs to be well understood (I recognise that much of the current Air Law exam misses the actual needs of a PPL). Application of this basic knowledge, in the main, will need to be applied during every day flying. As an examiner I can say without any hesitation that the lack of understanding of those that have followed the quick fix, is a very real problem.
One or two day courses can help many, that have already done a fair amount of self study, to get a better grip. However for those that are allowed to just turn up with the expectation that within a few hours they will pass an exam are being sold short.
Only an examiner will know the content of the current exam papers. It is an abuse of the examiner appointment to set up short courses, within which only the minimum knowledge, to tick the particular questions of a particular exam paper which is put before them the same day. i.e. before it has all been forgotten!