After reading Crash's blog with all his Garden Guests I wondered why we hadn't seen any snakes for a while. Then two appeared within a week or so.
The take-home message in all of this is that with Australian snakes it is often difficult to tell whether you have a harmless creature or one that could send you to the hospital. The best solution is just to leave them alone and they will be on their way. If one enters the house, the police department can provide access to local "snake removers" who will come and remove the snake at no cost and relocate it to where it will not cause any harm.
Thanks to Michael Cermak and Peter Shanahan for help with the identifications.