If you ever park in public you don't want the possibility that someone turns them on and drain tour battery ....
I've used a relay and controlled it by the switched power from behind the headlights. I've hidden the relay in the side of the fairing.
http://www.tenere.dk/forumnew/forum_...ID=72331#72331
It is cheap grips from hein gericke with a controller from mccoi.de