My understanding was that the first whites were seen by the blacks as a resource to help them fight their real enemies, that is the other tribes.
There could have easily been a "treaty" formed between the first fleeters and any local abos they could find, in fact there was between John Batman in what is now Melbourne. They could only catch up with a lame old woman, but instead of killing her, they gave her mirrors and blankets and a bit of paper asking her to sell them Victoria. She signed ok, and the batman lot were sorely upset when the govt, then based in Sydney, refused to honour the sale.