In quite a few research papers it has been pointed out that coincidental and emergent gameplay can produce fascinating pervasive play experiences. In addition to our Prosopopeia/Momentum research, at least Jane McGonigal, Steve Benford’s group have pointed it out.
I’m reading Josephine Reid’s DIMEA 2008 paper Designing for Coincidence (ACM), which takes a nice, fresh approach to the job: What about you go to your future playground, observe what’s generally happening, and plan your game around those typical incidences.
Definitely a paper we should have cited in Pervasive Games. Unfortunately, we only got time to read again after submitting the manuscript. In fact, that’s one of the reasons we have this blog: To discuss stuff we failed to put between those covers.