I do not necessarily think that they can "get away" with anything. Unless FIRST wants to go around and supply teams with copies of Windows and a shiny new MacIntel, Parallels may not be an option for all.
On another note, I have always been a mac person (since 0s6), and have found that there are 4 approaches to this problem:
1. Buy an intel mac (seriously, thats what I did) and run WINE (or parallels)
2. Use DARWINE PPC. (It will probably be slow, however)
3. Buy a windows machine. (used, ebay, cheap)
4. Use an x86 machine at your school (and write the code on your mac)
Even though I do own a macintel, I usually just use option #4. Most of our code is based on the school machines anyway, so whatever I write at home, I just either bring in on a pen drive or upload it to an SVN repo. (or ftp server)
I hope this helps! If you have any more Mac questions... Well.... you can ask me
-Jordan