As Gilles has said in his other answerhis other answer "version tags are massively overused on AU", I think is our fault that such things happens. We allow them be alone we them shouldn't and we do nothing to fix that. So, when an user ask a new question and gets offered XX.XX as only tag, is obvious that the user will only use that tag unless the system offers more tags.
So, I think that the system shouldn't suggest the tag at all, and let the user to explicitly tag it as such instead of suggesting it to prevent that questions gets tagged with only this tag.
