"Paid" wardriving does exist, when you gather data that has value to for example cell phone companies: NYC Taxicabs to Test Cell Signal Strength an AP news item about Ericsson installing small receivers in taxicabs in New York to do measurements of cell phone signal strength. I have been thinking about this, if you gather enough data about radio signals and other location-dependent measurements in one go maybe it could be commercially viable to just drive (or let a unit be driven) around the country. I can imagine radio and television reception data (especially with the change to digital services) is also interesting.