In that particular instance, I'd be peeved too and probably would've put it on anyway - nobody disses my Disney

Seriously, though, normally I would change plans if it means someone misses out due to religion/allergies/other things not under the kids' control. If it was something that was the kids' decision, it'd be a case-by-case basis.

It's strange though, for a great deal of it the magic's shown negatively in Frozen :-/ And I can only think of a few kids' stories that don't involve magic/fantasy of some kind - where does the little girl get her entertainment?