Originally Posted by tdol

I think this is down to the idea that we have a future tense, but it comes down to a big-endian/little-endian argument in the end. However, given that the present can carry the futurity idea, there has to be a demonstrable purpose behind using 'will' in the if-clause, which I don't think the future tense purists can explain away. If the present can carry futurity, then the modal has to carry meaning when used, and it isn't often used, unless the two are completely interchangeable, which I don't think is true.