I think I FOUND this forum because of cracks similar to the one you've posted.
From all the cracks I've seen similar to the one you linked, I would think it would be caused more by people putting pressure on their closed macbooks, rather than heavy-palmed users, as the linked article would suggest.
The cracks match up perfectly with the raised edge on the lcd screen, which would suggest that perhaps people are stacking stuff on top of their macbooks, or the macbooks are getting crushed in those bags with the "padded laptop compartments". I don't think padding is going to relieve the 50 pounds of book weight some students are schlepping around.