A guy interviews with a company. The guy doesn't get the job.
Three years later, the guy sits down in a coffee shop. He pulls out his phone, opens the Foursquare app. Scans for nearby businesses. Sees that the company is right nearby. The guy leaves a tip on Foursquare about how much the company sucks anyway. The comment looks like it might have been left by a customer. Or an expert reviewer. Since the company is not a dining or entertainment establishment frequented by heavy Foursquare users, the tip lingers near the top of its venue page.
It's like drive-by yelping. There isn't much I can think of that can be done about it. Or about a bunch of dissatisfied strangers flashmobbing outside your windows -- they don't have to be inside to check in and leave tips -- and populating your venue page -- that Foursquare creates automatically for you and that probably ranks pretty high in search results -- with their grievances. There isn't a lot of context to these tips. There isn't an easy way to reply to them. Deleting them isn't easy either, and is probably not a good idea anyway.
So there, something else to add to your social media policies checklist.
Good thing there's still time before Foursquare becomes mainstream.