Hi Snowman,
It was a great stir......I still maintain that the variations within YBS versus RES are quite broad and overlapping. You can get hatchie YBS with no trace of red or orange which is what I am familiar with and you can get RES hatchies with pale/pastel red....similar to YBS.
As they are both subspecies of the same species, I wouldn't be surprised if there is not some degree of interbreeding of the two subspecies, particularly in countries that they are not endemic to.
The other thing is that there are very few YBS in Australia....I only know of a few in Zoos....compared to thousands of RES in Australia, including feral populations in the wild. So given that you eluded that they were in Oz, everyone said RES, myself included.
See the thread that was created about this in australianfreshwaterturtles.com.au. I believe it was called 'Turtle I.D' by Zoojas. Personally, I still believe they are RES.
Kind regards,
Gab