I agree.. I think it comes down to the dynamic in the individual family. I consider myself aunty to DH's sibling's children, and vice-versa. I also think it is very much affected by the ties you form with those kids, if it's a step-relative you have only met once or twice then of course you will feel differently; I guess if you had much more close contact over the next year or two you would start to feel differently KWIM?
FWIW I had an Aunty who divorced out of our family when I was very young, 5 or 6, and we still are in contact with her & I still consider her my aunty :)

