Easy, all theme parks/amusement parks/tourist attractions (well, most) hire Market Research firms to gather info. Ever walk in a shopping mall, public area, etc. and have someone with a clipboard/pad ask you a few questions, then might invite you to sit down for an interview offering you a gift/cash for your time?How can they survey someone who is not in their park?
How about in an e-mail? Click on an ad?
Visit Anaheim does it as a Destination Marketing Organization (DMO) Aka Tourism Bureau. And Disneyland does partner in and adds questions they want answers to from the general public.