this easy trick is really funny :). I can imagine a lot of frauds thanks to such a trick. Don't forget that in some countries facebook helps police to investigate on crimes. Being able to prove your presence on another place rather the place you have been, it's really dangerous.
I definitely like Facebook company, but I think they need a little of "security reinforcement" :).
BlackBerry simulator allows you to tweak the GPS to any location on the planet, and the applications on the device respond as such. Of course this is just to test out applications, but why nobody has used it on Facebook Places before is beyond me. But then again, Facebook Places has only been out for the BlackBerry this past week, so it's not much time to really click on to this sort of thing.By editing the GPS location through Simulate > Add > then editing the Name, Latitude and Longitude, which you can get by enabling the LatLong tool on Google Maps Labs, you can spoof your Facebook Places into thinking you're in one place when you're not. Always add more than 7 satellites though as this makes the device think you are in a more accurate location than it is.