Yep! Guilty - over thinking.
LIke I mentioned, had seen a site such as described ... K12 - elem, intermediate, jh, and a hs. Lesser used elem and Intermediate campuses.
Once admin got them all to a version, that's where they stayed the remainder of that academic year. No look-sees at themes nor plugins. Now I know I've never seen a '0 day flaw' officially announced concerning Moodle code but did see one about libraries used by Moodle code the other day. Personally, I get nervous if not running supported anything.
And one of these days, I'll learn not to respond in developers! :| ... just 'lurk' in learning mode.