[icegreentea]

Yup... I don't think anyone is going to argue that Australia in fact has a higher population density than China.

In fact, the effects of 2) are reinforced even more, since my guess is that many, if not the majority of these findings were by scientific studies/surveys (note that they typically list the date found, not the date it occured). And since no one likes wasting their time, they would obviously pick areas where it would be easiest to find evidence.