Though not a fan of Noi, I must however stand by her. I staunchly believe that she addressed Kob as p' out of respect for Kob's endearing long career in the entertainment industry. This is polite and very good manners, in my opinion.
Though I am not Thai (my partner is) and I have lived in Thailand before, I find it common in the beautiful Thai culture to address other people as p' out of respect. I noted that should the one being address p' is younger and prefers to be called n' instead, he/ she will tend to laughingly broach the age issue and point out the prefered way to be addressed.