I currently have a "store locator" proximity search setup very similar to the one detailed here: http://www.youtube.com/watch?v=AxeskzN8BAc.
The user enters a postcode, and receives results or no results as the case may be, for a given rectangular distance (say 100km around the entered postcode). Both postcode and distance are exposed filters.
If a node/marker isn't within the zone, I get no results. How can I dynamically modify or widen the distance so there are always some results? ie. How can I hook onto the exposed filter arguments and re-run the view for the no-results case?