Raksha you already said you "didn't believe it" in another thread, until me or someone else linked the discussion with the tests (was it on BG? On FFXIAH? I don't remember).
I'm aware it wasn't a particularly extensive set, but there also were very little doubts hinting at something else.
It's just a very small chance of generating 0 enmity while casting a spell, period.
Not worth to take off your -enmity gearset, you can't "control" when the proc happens, and anyway it's a very low percentage.