In original post you state this:
The Display Names project is about the freedom to express yourselves inworld -- including using the tag above your head. As people live out their Second Lives their needs for the name above their head may change -- perhaps they meet someone and fall in love, or they make a new professional affiliation or decide to roleplay. This is why an important principle behind this change is that Display Names not be unique or limited.
This freedom is all very well and I think it is fine to give the option to users who share this wish. I can also see why it is a su