The armchair planner in me was a little taken aback at first by the description of the flea market as "amazingly good urbanism" -- good urbanism looks like bike lanes and trees and mixed-use development, not parking lots! -- but of course that's falling into the very thought trap illustrated by the post.
Parking lot flea markets are exactly 'tactical urbanism' in the same mode as pop-up bike and bus lanes -- the repurposing of car storage for more economically valuable and human-centric use, and (us) urbanist types should talk about them more often!