Much as I love technology and gadgets, they have their downside. Mobiles on trains are just ANNOYING, and bluetooth headsets mark the wearer out as, well SAD.
Following the advice of the great Bob Marley we can, for about $25, buy a device that jams annoying mobile calls. Click the switch and it sends out a blast of radio waves that stops the call. This has become something of a sport with jamming commuters. They wait until the caller gets through and jam it just one sentence into the conversation. "Wicked man.....CLICK, "Off to Tuscany tomorrow...CLICK. Wonderful!
On Bluetooth, I think it should be made legal to hit anyone wearing said device on the head, with a baseball bat. You might as well tattoo 'I'M A TOTAL PRAT' on your forehead. Note, of course, that this picture shows something you never see in real life - a woman wearing the device - never happens, they're far too sensible.