Note that "unlocking and rooting" a device causes it to be wiped back to factory defaults, which is why I do that as soon as I remember to with a new device.

A friend of mine has a Nexus S handset that has never been rooted, and he's gradually becoming keen enough to want it rooted (so he can use external USB storage etc..). If/when he finally says "yes", we'll then have a perfect guinea pig to experiment on.