"To be declared a Winner, a Potential Winner from Canada will be required to correctly answer, without assistance of any kind, whether mechanical or otherwise, a 4-function mathematical skill-testing question in no more than 5 minutes, the test to be administered by mail or telephone."
Anecdotal: I once nearly entered a contest (for a vacation or a sports car or something) whose "entry form" was, according to the fine print on the back, an application to have local telephone service switched to some no-name company. I didn't enter.
I've run into more but the Mary Kay one is the only direct quote I have available. If you find one I'd like to hear about it.
Obligatory counter: