I definitely don't rely on it, I agree with you. I think what happens is I have moments of thinking I should be able to merge, then checking the indicator and realizing I was wrong. In those cases it's very likely I'd do a thorough check, but it's a great reminder otherwise that my gut sense of my surrounding is incorrect, and I do need to check thoroughly and, for lack of a better explanation, assume I'm always wrong until I've fully checked my surroundings.