Actually under EASA before the MCC certificate can be awarded the student must reach a "satisfactory standard". This means that all quality ATO's will have the exercises graded with minimum standards required. Each ATO is required to have their syllabus approved by the relevant NAA. This syllabus must cover the minimum requirements as stated by Part FCL and the associated GM's and AMC's. The ATO can submit a syllabus that exceeds this minimum requirement and if it's approved then the ATO must deliver that course.
In my many years of dealing with the UK CAA the Authority always insisted that the ATO is not obliged to issue a certificate if the student does not demonstrate sufficient standards, i.e. the MCC course is not to be considered attendance only.