Saints Row IV has been refused classification in Australia, but Australians heading to Steam are still being offered the chance to pre-order the game. Australians heading to the game's page on Steam are now being offered the chance to pre-order a "Low Violence Version".
It's possible that Deep Silver is continuing to sell pre-orders anticipating that a modified version of the game will make it past the Classification Board at a future date. Deep Silver has already stated it is "reworking some of the code to create a version of the game for this territory by removing the content which could cause offence". It could be the case that this "Low Violence Version" is referring to that.
We asked Deep Silver but received a "Deep Silver has no further comments at this time" response, and a quick call to the Classification Board confirmed that it was not aware that pre-orders for Saints Row IV were still being offered on Steam.
A strange situation indeed. We'll update if any new information surfaces.