At my faculty (www.ii.edu.mk), and almost everywhere on the Balkans, during exams cell phones, pdas, iPods, etc... are forbidden. Only calculators. On some exams even calculators with function drawing capabilities are forbidden because it's the point to show that you know how to do it manually.
What kind of exam is that with phones and touch based devices? Even if you don't use communication, you can scan the whole book into pictures and read it during the exam. That's cheating.
"I'm thinking of buying 30 el-cheapo four-function calculators out of my pocket, but I'm afraid that less-adaptable students will be unable to handle the switch from the calculator they know to an unfamiliar (but simpler) one." -- If a physics student can't use a basic calculator, It's time for him first to figure that out, and after that to think on taking the exam.
It's a naive, domestic operating system without any breeding, but I think you'll be amused by its presumption.