Steinberger string adapter for non-double ball strings

Hey Everyone,

I just received a Steinberger Spirit (it's like the 6th one of those that I've had over the last couple of years - you know you can sell 'em on ebay and not lose money? especially if you buy them used and don't overpay). This time I got the string adapter that allows use of regular strings (instead of requiring double-ball strings). I did this so I can play with different string guages and tunings without having to buy expensive double-ball strings (but get the advantage of the zero fret and no nut so I don't have to mess with that).

My question: It looks like it pretty much just sits on top of the headpiece. It doesn't have any way to "lock on". So is it just being held on by the pressure/string tension? That seems fairly unsafe - has anyone ever used one and had it come off under tension? Has anyone used one for years with no problems?

Just looking for some reassurance that it won't be a deadly weapon.