Multiple foul

[Adam]

The rule is there because they don't want the shooter being fair game for extra contact after the first foul. I've never seen it called, and I can only imagine a very specific scenario where I might call it.

Shooter goes up and get fouled shortly after beginning the shooting motion, ref blows whistle, 2nd defender goes up to block shot and flies into the shooter knocking him to the floor.

Both of these fouls would need to be too serious to ignore but not enough for an intentional.

As others here, I've never seen it called nor do I ever intend to do so.

It's like the 10 seconds for a free throw rule. It's there to keep teams from using the opportunity for a de facto timeout, but most officials have never seen it called.