Mike Blumenthal has been covering the abuses in Google Local performed by less reputable local search marketers. There are a few problems going on right now, but one that has raised a lot of attention is the hijacking issue.
One way of dealing with this issue is clearly through litigation. A woman in New Zealand faces up to 7 years in jail for taking ownership of other people’s businesses without their permission.
Hijacking problems have been rampant in the floral, payday loan, and locksmith industries (see Mike Blumenthal’s blog for more details) There are most likely many others that are less visible where this is happening as well. Google is certainly trying to build solutions to deal with the issue, but it’ll be awhile before their technology can spot problematic listings before they go live.