Biccy, it all depends on how big the fish was. If it was a senior player at ASA they could have a very high monthly allowance and therefore racked up the bill rather quickly, without raising to much suspicion. However if they were purchasing $2k per night call girls, Versace handbags, big screen TV's from Harvey Normans or gold bullion from the Perth mint you might think it would have been picked up sooner? It could have also been done on a smaller scale with smaller amounts over a long period of time. It's a tad hard not having all the details on hand to make a totally accurate summation. It also could have been a more lowly ranked minion who has enjoyed splurging a little on some of life's finer trappings - fuel for the 182, KFC for the family, inflatable balls to take to the MCG for the cricket or 'interesting attire' for the next Hellfire party at Hoody's place!
Either way, the rorter was obviously a thorough buffoon. It's not hard when you are a public servant to use taxpayers money to further your own personal advantage and make it all appear 'legitimate' and 'above board'. Then again maybe the ASA person will use the CASA excuse and say that the $20k of transactions was due to his wallet accidentally brushing past pay wave machines and somehow charging up said items?