Don't announce the times. Have HOSTs randomly come on, when they want, and use the random program for however long they want. Give them a limit if it becomes an issue (say, no more than 30 minutes at one time, no more than 50 runs of the program per day or similar).
That way it's truly "play the game and you have a chance". Not "get on at these times, and wait in a room"
That way it's truly "play the game and you have a chance". Not "get on at these times, and wait in a room"