Apparently, this is not unusual. The pests are very tough and resilient.
In the above case, quarantine authorities would not comment, though a spokesperson did try to make out that it was a tree frog. The owner of the shoe lived in Brisbane for many years and said it was definitely a cane toad.
It seems cane toads won't have to walk across the top of Australia (as they steadily are). Crossing the country is far easier by plane.
Cane toads are intelligent as well. It is known that if water is scarce they will follow a cow drawing moisture from cow pats until the cow eventually reaches a river or dam.