When a show is created on the calendar, there is an optional “Autoloading playlist” which fills this show with a playlist one hour before this show airs.
A similar feature “Autoloading smartblock” should be much more useful, as content added would be randomnly generated.
I think that “Autoloading smartblock” could interess other LT users.
Could such feature be added to roadmap ?
So the basic way this works is you just put a smartblock inside of the playlist and you get an autoloading smartblock. It is an extra step but will serve the purpose you proposed. In addition you can add a time remaining in show filter for the smartblock and have it try to add tracks to fill the show.