Also note that in the majority of schools you have already payed to use mathworks (through tuition) if you are in any engineering program. I don't know why it would be so much more ethical to pay twice...
So, if you want to support mathworks/photoshop/etc then you should encourage broke students to get it on their home computers by any means possible. Many of these companies practice this strategy. Thus ends my pricing hypothesis.
Paying tuition does not mean that have "paid to use" Matlab unless your institution has actually bought licenses for you to do so. If you are saying, "We were using a floating license paid for by the university and therefore did not need to purchase an additional license." Okay, fine. If you are arguing that because the physics department bought two licenses for lab machines that you somehow have the right to pirate copies without a license then you are mistaken.
Bottom line: I support the good guys, the companies that respect me and help me to do the best work I can. The Mathworks is one of those companies, in my experience.