Liz, that makes perfect sense in retrospect. However, many venues do not require testing for folks who remain masked and have had a "test in to unmask" approach for performers while on stage (where they were masked elsewhere and, until receiving a negative result, on stage as well).
Greenfield's own central policy states:
"Band members may unmask when on-stage for some series, but only if they have a negative rapid test on the day of the dance. Event publicity will clearly state whether performers may be unmasked at that specific event."
Note there's no specific timeline stated there for when the testing shall happen other than it be on the day of.
That's the point I'm raising from our recent experience.
-Don