How much migration was there between Australia, North America, and Eurasia 2k to 5k years ago?
Certainly they talk about it, but in no way does it seem that it was adequetly or accuratly accounted for in their conclusion.
This quote for me certainly raised a red flag.
Allowing very little migration, Rohde's simulation produced a date of about 5,000 B.C. for humanity's most recent common ancestor. Assuming a higher, but still realistic, migration rate produced a shockingly recent date of around 1 A.D.
If someone could calculate a "realistic" migration rate between Native Australian and European people then that alone would probably be news worthy. What it sounds like they are doing is applying a rate taken from analyzing some migration dynamics and applied it to the whole population. A step that if true would be very much invalid.
The other think you should note is that by slightly changing their "rate" they give a number that I would be hightly skeptical of 1 A.D. I would need more details to be sure but at first glance that just seems rediculous.
Of course, biblical creationists are committed to belief in God's written Word, the Bible, which forbids bearing false witness; --AIG (lest they forget)