Steering head lock?
You must be joking. Of the 31 (yes, really) BMWs I have owned, NONE of them worked. I just pulled the key out and walked away from many bars and weird areas wherever. Weird bars too.
They are, without question, about as good as tits on a boy. No nourishment there.
BMW used to sell a great red rubbery brass lock that folded. Now that is the biz. Not only is it great for locking up a rear wheel (perfect for New Orleans... trust me rangers, or go and find out yourself). You can also use it as protection in hinky situations. Fully extended, it's got a 5 foot reach. Start swinging that head height.
People back up.
Security and safety.
'66 BMW R60/2, '83 BMW R100RS,'81 BMW R100RS "Das Beast", '87 BMW R850R '77 Honda XL125