"Willfull Indifference?"

[greymule]

I got in on this thread late, but in 50 years I never heard the term "willful indifference," only "defensive indifference," as when, with a runner on 1B, a pitcher goes to the windup 10 runs up with 2 out in the 9th.

The PBUC has a section on "Willful and Deliberate Interference," which covers 7.09(g) and 7.09(h), obvious interference with the intent to break up a double play. Did someone perhaps mistake the words interference and indifference?