You mistake my use of anticipated. I agree with you, I meant the change was anticipated as in "It was expected to happen". It was in the cards to happen eventually, whether it was intelligent or not.
Returning null in the math library at all just seems counter-intuitive.
What kind of programmer passes "" and null on a function such as this and expects ....zero in return?
And what kind of programmer does it --as he admits-- "all around the place"?
If you give right to this guy, that's a very very short and accurate interview question --no hire.