The 'cyberstalker' in the article called the woman on the restaurant's telphone, not her telephone. Also, the default privacy settings on Foursquare allow users

The 'cyberstalker' in the article called the woman on the restaurant's telphone, not her telephone. Also, the default privacy settings on Foursquare allow users who aren't your 'friends' to discover when you've checked in somewhere via the 'mayor' and 'who's here' features.