I can't say that I've ever read a published pure maths paper - if I did it was so long ago I have forgotten.

OTOH, every time I have seen the Fibonacci Sequence defined it has been like this:

• F₀ = 0
• F₁ = 1
• F_n = F_n-1 + F_n-2 (for n > 1)

Perhaps it is the exception? I voted for zero anyway. Cardinal, not ordinal. But you are right that having the choice is good.