This mechanism was implemented to fulfil a need of my department here at the Istanbul Technical University. At the end of each term we present students with questionnaires for each course they have taken in that term. Since our students have no users on our site, we decided to hand out tickets that would enable them to fillout the questionnaires even as anonymous visitors. If you have a similar case, here's how it works:

• when editing the questionnaire, check use_ticket
• go to the tickets tab and create as many tickets as you like (multiples of 15 are recommended, since they can be printed out on a page)
• select list available tickets and print that page (note: the number of tickets displayed are always a multiple of 3, so you may not be able to see the last 1 or 2 tickets)
• hand out the tickets to people you would like to participate in the questionnaire