I liked how you think Apple offer a discount as a 'Goodwill'.
At least in the UK. A long time ago (Can't be bothered to search but feel free), Apple signed an HE agreement to sell to educational institutions, part of the discount agreement was that there would be a discount for staff and students of the institutions. Lowering the discount was likely them signing a new agreement with a reduced discount. I'm fairly sure they'd rather not offer any discount what so ever if they could.
I suppose you could technically call it fraud, however I think the truth is that they sell more units this way as many people who would look elsewhere are buying the Macs instead. Also pretty certain their profit margins cover it nicely. Also as a student you're entitled to the discount for 1 Mac per year, and you do have to be a student to get that discount. So if you waste it on someone else you're only screwing over yourself... Not defending anything, just clarifying. Caveat, with the amount of tax evasion Apple does (And everyone else for that matter), it's a bit of a pot/kettle situation anyway