Surely they wouldn’t do that, would they? Perhaps not intentionally, but according to a new study from researchers at the UCLA, it’s far more common than anyone seems to realize.

Computer World first reported that some (but not all) carriers may be unintentionally charging their customers for data that they never receive. It happens due to the flawed way in which they only measure outgoing data from their servers, as opposed to the data that their customer’s cell phones actually pick up.

The problem arises whenever a phone loses its signal. Should the phone be receiving data when this occurs (like, all the time…), some of that data ends up getting ‘lost’, bouncing around the airwaves for eternity, but carriers charge you for it nevertheless. The researchers did an experiment to prove their theory, jumping on a train and watching a YouTube video as they passed through several tunnels – after comparing how much data they received, they found that their carrier had overcharged them by 7.2%. Meanwhile, another test under more extreme conditions incurred a charge for 450MB of data that they didn’t receive.

Obviously the big concern is just how often this happens. Depending on how bad the service is in your area, you could potentially be losing a lot of data, and still be paying for it. Although, those who live in cities with a good quality signal probably don’t have too much to worry about.

It’s not all bad news though. In the same paper, the researchers also revealed a method through which more technically-minded cell phone users can actually circumvent their carriers’ data monitor entirely, potentially gaining access to an unlimited supply of data uploads that they’ll never need to spend a cent on. The method involves using an unmonitored port used for DNS queries, and allowed the team to send more than 200MB of data completely free of charge.

The goal of the research was not to ‘name and shame’ any particular carrier, explained co-author Guan-Hua Tu. He refused to name which carriers were found to be overcharging their customers, saying that the idea was just to draw attention to limitations within mobile data architecture, in the hope that carriers will seek to address these.

Click here to read the research paper in full.