Very cool, if true

Nope, that's being smart, just in a different way. None of my fellow teachers would grade students this way and expect them not to help each other. It's like giving the exact same test to different classes on different days and not expect the second class to ask the first one what the questions on the test and were and learn all the answers by heart. If you really want to see if the students have read and understood the material, simple quizzes with recycled questions aren't the way to go. It's lazy testing and, in my country, a mistake only something some very inexperienced teachers would do.