Over the last few years, our university has seen a rise in high-tech academic dishonesty. We have a no electronics policy, except calculators when needed (even those now are provided by the school, and personal calculators are not allowed). However, students still sneak cell phones into the exam and use them in a very inconspicuous way.
We have had students take pictures (presumably with a cell phone) during an exam and have someone outside the room sending them back solutions. We have had them communicate with classmates somewhere else in the room (some have been caught this way giving the right answers to the wrong exam). We have had numerous students using their phones to store notes, copies of old exam solutions, etc., and use them as an aid during the exam (this is the most common).
We have caught some students, but I know it is a small fraction. Students will tell us they see cell phone use routinely during exams, but don't want to squeal on classmates because of anticipated reprisal. Our instructors are quite vigilant in watching the classroom, but it is very difficult to watch 30 to 70 students constantly. (Larger classes have multiple proctors.) Instructors have been informed of the classic cues as well. Our penalties are stiff (first offense, F in the course, second offense, student gets the boot from the school). However, students are still getting away with high-tech cheating.
My question is, does anyone have any sure fire ways of identifying students attempting to use cell phones or other high-tech cheating devices during exams? I'm looking for methods, electronic sniffers, etc.