Fan of the service, I think it has potential. But once it become actually influential (free drinks!) how will they protect against spam? What's to stop me chec

Fan of the service, I think it has potential. But once it become actually influential (free drinks!) how will they protect against spam? What's to stop me checking in a hundred times at a venue (or alternating 2, so I don't have to "re-check in") and becoming the mayor?