If the police officers and border guards were forced to wear them, they perhaps would have an incentive to treat you decently and not to violate your rights.
If worn by participants in a demonstration, also interesting, especially if streamed live.
The argument of equalizing the relation between the powerful and the powerless in surveillance does have merit. Especially when the NSA is currently building a 65 Megawatts datacenter, where they will have the possibility to trace everyone whereabouts.
From another commnent: yes a red LED will blink when recording.