When you signed up for cellphone service, I bet you didn’t expect that your exact location could be sold to anyone for a few hundred dollars. The truth is, your wireless carrier tracks you everywhere you go, whether you like it or not. When used appropriately, this tracking shouldn’t be a problem: location information allows emergency services to find you when you need them most.

But wireless carriers have been selling our data in ways that allows it to be resold for potentially dangerous purposes. For instance, stalkers and abusive domestic partners have used location data to track, threaten and attack victims. This industrywide practice facilitates “pay to track” schemes that appear to violate the law and Federal Communications Commission rules.

Companies are collecting and profiting from our private data in hidden ways that leave us vulnerable. As you carry your phone, your wireless carrier records its location so calls and texts can reach you. And you can't opt out of sharing location data with your carrier, as you can with a mobile application. Your carrier needs this data to deliver service. But, according to recent news reports, this real-time phone location data has long been available to entities beyond your wireless carrier, for a price. In one alarming example, reported by Vice, a bounty hunter was able to pay to track a user’s location on a map accurate to within a few feet. In another case, a sheriff in Missouri used location data provided by carriers to inappropriately track a judge.