Yep, you're right. VFR flights do tend to be a problem. There's always a number of things in the system producing radar echos without clues, and those are honestly just stripped out to simplify matters.

Regarding the FAA data: We obtained the data, but not easily. We actually had to basically get a bill approved in congress that granted access to the data. There are 6 companies originally that have primary access to that data. Of the 6 companies, only a couple are in the business of selling the data. Other companies have secondary access to the data by way of purchase from us.

Of course, today, we have access to a much greater amount of information than FAA ground radar. We really can find out names and addresses! The FAA does not furnish passenger records of course, but I'll give you two guesses ;-).

Something to think about:

There's a company across town that does people-tracking. They have access to cell phone data, and the initial feed of triangulated-longitude-latitude numbers on a per cell phone basis. They're using that data semi-anonymously to compute traffic congestion. They have a nifty plot/visualization that shows all these dots fuzzing along the highways. They can compute the average speed based on the cell phones! cute. ;-) Two guesses as to what company that is?

Calvin