You know what's real fun? Losing a snake, then having that snake go to another rack and pushing out all of the tubs on that shelf in an effort to get to the heat tape in the back thereby freeing several more snakes. Believe me, it's a load of fun.
One thing that's good to do before losing your snake, is to seal off all of the holes and cracks in your walls so that they can't get into the wall or move to another room. A product called 'great stuff' is your friend in this endevor.
I've found one of the best ways to find a lost snake is a quiet room and a flashlight.