content: Most likely - at least in the early-to-mid stages of browser adoption - the browser will prompt the user for the ability to access Bluetooth devices if available. If you notice even today, you will be prompted when going full screen for video features until you decide to tell the browser to "remember" that it's ok to go fullscreen on that website. That said there is probably room for abuse, but I expect browsers won't open the floodgates for it unless it becomes a very popular API, which I really doubt will be the case.