Oh, go ahead and say it.  Management says:

Callers should ask the band to play a last waltz BUT should not
announce it as such. To announce the last waltz as a last waltz is
to make the beginners feel left out. If you don't announce it then
everything is fine.

I'll say it out loud. That's silly.

Per Karen's note, if you have lots of newcomers who don't know how to waltz, a mini-lesson at the break would be nice.    

Has anything like this come up in your dance community? I am trying
to have an open mind.

Nope.  this is a brand new matter of (in my opinion -- unnecessary) concern.


When you stumble, make it part of the dance.