Maybe instead of getting a list of the YES/NO lists, if there was a pre-determined list of 'themes,' the ST could log in what themes were going to be in place.
The list doesn't even have to be published.
But if it was on your 'NO' list, you could get an @mail:
'As a note, the +event you signed up for (#1929, Stuff Happening) has been flagged as potentially including the following:
- Drug Use
- Domestic Abuse
If you wish to step out, please retract your RSVP.'
That way people would have their own sort of personal 'out'? Without any spoilers or peoples' triggers being directly/specifically outed anywhere?