"If fair" needed in SP?

[bainsey]

I've been umping my town's co-ed SP rec league for over a decade. I had formal ASA training in another town, but I've been working steadily in my town since, while studying on my own, so I'm truly working without a mentor. Here's something that never occurred to me until recently.

Infield fly rule in effect, pop-up in the infield near a foul line. I've been saying "Infield fly, if fair!"

If the batter has two strikes and hits a playable infield pop-up (0 or 1 out, of course), is "if fair" even necessary? If the ball lands foul, the BR is out, and the ball is dead, anyway. Granted, the batter would be out on strikes, rather than the infield fly rule, but how much does this matter?