Mall audiences, dream surveys

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Mall customers. Who are they, what do they do? How can we know?
AdSpace, a huge network of 140 American malls with 1,800 digital billboards, studies shoppers' mall experience. The loop on the digital screens lasts 4 minutes with a mix of commercials (local and national) as well as news briefs on people and fashion. 
USA TouchPoints is going to study visitor behavior: "their mindset and receptivity to media exposure".
The survey will enroll 2,000 people; each of whom will report his/her activity and mood on an iPhone, every 30 minutes (using a kind of eDiary). The survey is planned to last 10 days.

Nice survey indeed. But...

• It seems to be very intrusive. Who wants to stop and register their behavior and mood while shopping? 
• It is declarative.  Do we believe everyone is going to be honest in explaining their shopper emotions and mindset? Who is even aware of them or how to express them? "Everybody lies", as Dr. House says! Hopefully, he lies too!
• Who would participate in such a sample? People who are not too busy, people with no kids around. Idle, with nothing else to do. How representative could such a sample be? 
• The mall is open 365 days. Will the 10 days of the survey be representative (weather, events, traffic, etc.)? How about seasonality?

The survey we all dream of ...

• Would last all day long, all year long.
• People would not know that they were being surveyed: it would be totally anonymous. We would only know whether they were male or female, old or young.
• We would learn where people go, inch by inch; where they stop, in which store. When and for how long, second by second: the consumer paths. We would know if they were close to a screen and even which part of the loop they watched.
• We would learn the rhythm of their visits. 
• All while respecting their privacy.

How would you improve that dream?
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