FourSquare has added an updated Do's and Don'ts list in their "house rules" page. "The guidelines set by our community for how to make the most of foursquare and have the most fun," the site calls them.
The ruling on "jumping" - the signing in to numerous places around the world when you were never there to collect badges. "Don't check in when you're not at a place. Check in when you're actually at a place, and only check in one time when you're at a venue (remember: only one check-in per day at a venue counts towards Mayorships!). If you check in more often than when you're actually at a place, you will see the rapid fire check-in error message. Checking in across the globe is discouraged-we know you love badges, but it's only really fun if you earn them fairly"
The instructions addressing "jumping" do not prohibit the act out of hand. As the AboutFourSquare site notes:
"Enforcement would have to take place on a case-by-case basis after the fact. Given foursquare's open API, preventing jumping before it happens is nearly impossible. Many users have called for foursquare to shut down their mobile website, but that would merely slow jumpers down. There are plenty of ways that location can be faked that would be undetectable with foursquare's API, which must trust the latitude and longitude passed to it by the app. Foursquare has put in place checks that prevent checkins that couldn't reasonably happen by calculating flight time between two venues, but jumpers have built travel-time calculators (no, I won't link to it) to help determine how fast they can check in to earn badges."
The popularity may slow if badges are rescinded or some locations removed, but that has to be seen. Right now it has become a popular way to share location enjoyment - real or otherwise. And it doesn't seem to be slowing FourSquare partnerships with major content providers.