[AnimalMuppet]

We had a system that was used to generate television graphics. Our installer for new software was capable of bringing up a system with a new hard drive, so one of the options it had was to format the hard drive. The installer asked three times if you were sure, with increasingly severe warnings about losing all your data. Sure enough, a customer with an existing hard drive ran through all three warnings, formatted their hard drive, and then called customer service to complain about losing all their data.

The solution, of course, was to add a fourth question...

[mark-r]

A fourth question obviously isn't going to help. Make them enter "erase my drive" into a text box, that might get them to pause for a moment.

[strictfp]

Well, the probability approaches zero asymptotically as the number of questions approaches infinity...