I know alot of people are saying that they put their games on pause while moving the rubble in hopes that this will prevent collectables from appearing but this hasn't been my experience. I often put my game on pause to move villagers around and have seen collectables and mushrooms appear and dissapear while the game was on pause. Maybe it's just my game but pause seems to only stop the clock and the villagers from moving. I have even used pause when I want to make a baby and one of the villagers won't stop running around and have always been successful.