Questionnaire (plugin)

I've only recently tried out the Questionnaire module, and tried it out with a single-response survey for my class. I also found that for some questions some students had multiple responses - this causes strange results in the percentages (for example, for a yes/no questions I have had things like 100% yes and 20% no

I am suspecting this is due to the way my questionnaires are divided into sections. If a student logs in and starts the questionnaire and goes through a few pages but never submits, does the part that was answered still get into the database?

When you look at a restored one, is it still set to 'respond once'?

mike