Ah, Foursquare. Either you love it or you think it is even more dumb than Twitter. Either way, the fledgling social service which is now available in the Microsoft Marketplace and soon for Windows Phone 7, has updated some of their code to prevent people from cheating on 'check ins'.
See, the more often you 'check in' with Foursquare at a specific location, the better chance you have at being the number one visitor. Upon that amazing (or sad) achievement, you are awarded badges or the most coveted 'mayorship'. Yes, yes, it's also silly and a bit odd for adults, especially if it's a place of ill repute to indulge in your lascivious ways.
As bad as all that is, evidently people were cheating to get those awards by spoofing their location. For shame people. Well, Foursquare wants you to know they frown upon such behavior and have attempted to put an end to your evil-doing ways.
So there, neener-neener.