eBay is ok with pre-orders, dropshipping, and 'just in time fulfilment" (which is kind of a cross between pre-orders and dropshipping).
In the latter scenario, orders for items are made ideally in advance, for the projected sales volume of their product lines, which means the items in question should either be in a warehouse somewhere in Aus, or on their way to one from overseas, at the time a buyer places their order. The warehouse then does the dispatching. (Pre-orders is fairly self-explanatory, dropshipping is similar to JITF, except individual purchases are made for each order as they come in, and the supplier ships directly to the customer from overseas).
If they have a reasonable delivery time (that's being met), it's likely they are going the JITF route if they are sourcing from OS. This also allows them to put the item location as Australia (eBay have confirmed they are ok with this, even though at the time of ordering, the buyer's item may not be in Australia, because it ultimately (or eventually) dispatches from an Australian warehouse), unlike with dropshipping which requires the item location to be where it ships from (not all sellers follow that rule, though).
I don't agree with eBay's reasoning re: JITF, personally, but that's what the message has been when approached about the practice.
