I recall it being discussed here before, with the answer being Disney doesn't like the alcohol ads Playbill uses. The Disney shows in other theaters have no authority to change it so they stay playbills.
The funny part is I've not seen an overwhelming number of alcohol ads in Playbill of late. (I did a little trip down memory lane with my 80s and 90s Playbills-they were chock full of cigarette and liquor ads. That sure has changed. I might have spotted about a half dozen liquor ads since 1992 and nary a cigarette one.)
You're telling me! And even into the 80s. I sure remember a time when lots of people smoked. And the ads in the Playbills are a sign of the changing times and taboos. (Although I must say I've noticed a lot of smokers lately.)