Not just the NSA.
There have been several demonstrations that laptops and other Bluetooth-capable devices can be used to activate and then monitor monitor Bluetooth-capable cel lphones with not warning signal and without the owner’s knowledge.
Don’t take my word for it. There’s a list of known hacking risks on the official Bluetooth website
There was a demonstration of this at a major conference just a few days ago which addressed the Bluetooth SIG’s [rather off-base] dismissal that the risk required the tapper to be within Bluetooth’s short range. They set up a quick demo that a simple antenna could allow a laptop to hack into a phone from a mile away.
Other similar hacks have been demonstrated that allow the hacker to download your saved text messages, call logs – or even [and i find this chilling] insert forged entries or messages that never took place into your phone’s log or queue. Such in-phone logs have been used for DHS prosecutions, and I hate to think how backdated and inserted messages or log entries could be used in office politics.
I wish I could provide more details, but I’m not at home. You should be able to find the details on Goggle under >bluetooth cell-phone security risk<