[support] Is there a way to "lock" taxonomy selections for a node after publication?

I have many OG group node content types where both the URL and the title are created automatically from the taxonomy settings. So when a user creates a new group and selects the location to be USA >> Texas >> Dallas: Title: My Group (Texas, Dallas, USA) URL /group/usa/texas/dallas/mygroup Is there a way for me to prevent that group administrator/creator from going back and changing the taxonomy terms a year down the line and therefore changing both the title and, more importantly, the URL with all its implications for SEO, site organisation, broken links, etc.?? How can I "lock" taxonomy on publication? Is that doable? Regards Neil