Leaving home - it has to be said - is a very, VERY nice piece of business.
Sure, the handling's a little knacky to begin with, but it's relatively easy to pick up with a few day's worth of practise.
Just to address a point that's already been raised; I was a little surprised at the un-cut/blank key shaft too...before I realised that this very oddity actually suggests a couple of nice presentations:
For the younger folks, I introduce this as a replica TARDIS key, and patter about it being connected to the real TARDIS (yeah, I know...geek!!

), and sharing some of the same properties, like being able to dematerialise from the cord, and rematerialise underneath it, effectively freeing itself (then performing the first penetration).
Also - the key is actually able to travel through time; I let them see how the key is able to move back in time by exactly one minute, to the time it was still tied onto the cord (performing the return to cord)
The presentation I use with older folks is to say that it's a new front-door key, that I'm in the process of training. I explain that I was always loosing my old key, and eventually it went missing altogether.
Then I talk about our local key-cutter, being a little eccentric, and insisting that I wear an uncut key around my neck for at least a week, to 'train' it, before he would cut it for me, to ensure the new copy would never go missing.
I then demonstrate how the new key still isn't quite trained by penetrating it off the cord.
Finally, after some fun, describing how I'm going to discipline the key for it's naughty ways, I whip the key several times with the free end of the cord ("Bad Key...BAAAD key!" - I kid you not

), before re-penetrating it, and handing it out.
S'funny the things I think of when seeing something like an un-cut key, y'know....I'll be off, time to take my medication now
Rob