Good god! Final exams at Harvard are 'take home'? I really thought that at least Harvard was a little more testing than that... Aside from the standard that sets, it is naive to the extreme to suppose that students allowed to take an important exam home will still write it just off the top of their head.
Take home exams can actually be quite brutal, but are rarely encountered in large (i.e. 100+ student) classes because they usually result in an correspondingly brutal amount of marking. I've had them only in a few senior undergrad courses and grad school. Why are they brutal when you have your notes, books, the web, etc. available? They're usually not based on spitting back answers you were given or can look up. You…
The only stipulations for the exam was no collaboration and show all work.