Thanks. Since posting that I actually did try out the keyboard on one and found it was very nice, in fact. I was quite impressed with the build quality of their 2-in-1 Yogas. They've a higher end one the 9i which is even nicer, but that's quite a bit extra. I'd prefer the AMD one because more oomph but that has worse ports.
As to hitting people with it, I honestly think my forehead and elbows are more dangerous. It's only aluminium, after all and with the bevelled edges and rounded corners Lenovo do these days, they're not even sharp!