If you're running a competition as part of a survey, don't ask for my life story and all my personal details - all you need is contact information, a name and email/telephone number for example.
I just filled out a survey for a BFI IMAX in which a competition for 2 IMAX tickets were up for grabs. The moment it asked for an address I closed it.
I'm happy to tell you my experiences I had in your cinema, but don't take the piss.