The use of an Australian customs vessel or the like, can be done in a sensible way, but there are some specific things any expedition of this kind must keep in mind.
Firstly, before any voyage of an Australian vessel into Antarctic waters during the whaling season, the Australian Government must make it abundantly clear to all, including participants from both sides and the Japanese Government that we do not support the horrific slaughter of some of our most endangered creatures. It must also be made clear to all participants that the Government does not condone the cowboy actions of a select few activists that think vigilantism is the way.
So here is how such a patrol could work…
An Australian Customs vessel or similar would make its way into the area ahead of the commencement of the whaling season, preferably and if possible, prior to the arrival of the Japanese fleet.
Any Australian Government vessel proceeding to, or once in the whaling zone must not be seen to be “baby-sitting” the anti-whaling fleet. Communication between the Sea Shepherd group and others should be kept to a minimum whilst in the area.
Where possible any deliberate acts of sabotage from either side should be policed and dealt with appropriately.
There is no denying that such a move is difficult for the reasons discussed, but is not impossible and certainly not unworkable even if it causes a little diplomatic pain. However, in my view, the diplomatic grievance would be much larger from the ICJ case.