I feel certain that such a practice would fall under the descriptions of illegal practice in AMHA, and almost as certainly, in AMHR--as it SHOULD!
Personally, I REALLY dislike pink skin around the eyes--and I would shop elsewhere even if I liked EVERYTHING about a horse, and it had this feature-because I'm SURELY not having it tattooed!--(and a big reason I would never keep a cremello. I used to be very partial to frame overos, but have sort of 'slid' back over to more 'classic' tobianos, this being one big reason why!) I have ONE old mare with only partial pink skin around a blue eye, due to the way her bald-face marking lies--as for the sun, she wears a fly mask during the months of strong sun, as much to protect her eye from the sun as from flies. It works quite well.
Margo