See that rather ominous warning label above? That's a new sticker that will soon be placed directly on the screen of every new device Verizon Wireless sells. Contrary to what you might suspect, however, that's not being done in response to the most recent iPhone 4 tracking fiasco. The label was revealed in a letter to Representatives Ed Markey and Joe Barton, who themselves sent a letter to Verizon (and the three other major carriers) on March 29th inquiring about a New York Times story that raised concerns about how carriers collect and store personal location data. As for the other carriers' responses, they apparently aren't going as far as Verizon has with its warning label, but they do mostly echo Verizon's response in other respects. They all say, for instance, that personal data is secured by a variety of means and stored only as long as needed (which can apparently vary by carrier, though), that they don't rent or sell personal information, and that they request customer consent before accessing location data. Despite those assurances, however, Rep. Markey says he's still left with a "feeling of uneasiness and uncertainty," and he's pointing a finger at third-party developers in particular, who he says must be held "accountable."