Since the survey machines where so conveniently located, when I had a few minutes I would go ahead and fill in a few, but by the end of the 2nd day I couldn't remember which sessions I had reviewed. Since you ask for an email address with the survey, you should be able to link my surveys back to my account, and at least list the sessions I've reviewed, so I can see the gaps. Perhaps just a 3 day table with timeslots down the side, green with session review completed for this slot and white for not reviewed timeslot. No real need to try to tie this back to the session scheduler app