A lot of people are still using that part of a regex no matter what - I still run into this regularly (and have been, for two decades now).
"There is some danger that common usage and widespread sloppy coding will establish a de facto standard for e-mail addresses that is more restrictive than the recorded formal standard."
This is EXACTLY it. Both in the local part, and in TLDs - nothing clever about people being too clever by half, and generating false negatives on their input side.
"There is some danger that common usage and widespread sloppy coding will establish a de facto standard for e-mail addresses that is more restrictive than the recorded formal standard."
This is EXACTLY it. Both in the local part, and in TLDs - nothing clever about people being too clever by half, and generating false negatives on their input side.