Basically any business that is aimed at homeowners, but tends to be located away from residential areas, has a big inventive to create false locations.
I wrote that! Thanks for posting that. Here's a good article from an ex-Maps spammer, detailing how he used exploits in the Maps UI to hijack listings: http://valleywag.gawker.com/how-a-hacker-intercepted-fbi-and... Although that particular loophole is closed, there are still many ways to get spam listings on Maps.