Our Towns; Casinos' Allure: Weaning a Girl From the Tables
LEAD: The 12 casinos in Atlantic City say they turned away minors at the door 200,000 times last year and kicked them off casino floors more than 30,000 other times. The casinos say they do their best to keep out those under 21. If so, what is striking about the case of Kim Cohen, an Atlantic City teen-ager who started playing blackjack at 15, is the encouragement the casinos gave her to keep gambling.
