Wardriving is something necessary when you are too broke in America and every McBurgerHut has wifi. I wish I came across warchalks too. That would've been a great help
Don't forget: we have those crappy UPC routers everywhere. In every street, at least 5-10 are still upcgen affected and 1-3 usually never change the default passwords.
It gets worse once you dig deeper and find out how T-Online, vodafone and o2 hotspots work.
Agreed, although they seem on a mission to eliminate open wifi networks; the homepage has a prominent graph celebrating the growth over time of secured APs.