Of course there is, and has been, some slight-of-hand involved - the previous government was expert at it (and the Rudd trick of putting the NBN off-budget was also a notable lapse of fiscal transparency and integrity). But the Auditor-General closes loop-holes as quickly as they appear and it would actually be impossible to hide $2.4B in external transfers for more than a nano-second. Senate Estimates hearings are also a remarkably effective mechanism to keep Governments (reasonably) honest and accountable. That won't stop politically-inspired BS in unaccountable forums, of course - as you have ably demonstrated.
