Once when honing a blade that was a borderline frown on a narrow hone, I managed to turn it into a definite frown (not realizing until pretty late) and then had to hone that out. Lesson learned.
Py's honing rule #3 (learned from Py's stupid things to do with a hone #6):
Anything with even the suggestion of a frown doesn't see a hone under 3 inches wide.