A possible solution would be to split the job, to avoid conficts of interest. One teacher teaches. Another one grades. When I was studying in France in "prépa",

A possible solution would be to split the job, to avoid conficts of interest. One teacher teaches. Another one grades. When I was studying in France in "prépa", all students wanted to get a real evaluation of their level, because the really important exam to enter the best universities was organized nation-wide. But, this is hard to organize in private universities where students are also clients. Which parent would pay 40k$/y to be told that his kid does not study well? Maybe, here also, to avoid conflicts of interest, the job can be split. One university teaches. Another organization grades.