I can't imagine ever leaving a salon with WET HAIR!? To me, you should leave the salon ready to go out to dinner, on a date, etc. It's kind of a rip off to leave the salon with "incomplete" hair. I would also think its not good for the salons image, to have clients leaving with an unfinished hair do.
Curly hair in particular looks really different when its dry, so how can you know that you got the look you were seeking? If my stylist did this, it would be a big no-no for me.