Why do Playbill and other theatre guides always inform us which actors, stagehands, stage managers, etc. are members of the various actors and stage unions? After all, TV Guide doesn’t indicate this for every actor/actress. What gives?
To hazard a guess - it’s probably part of the contract between the union and the theater/production company. Particularly at the large mainstream theaters, shows are required to hire only union members for certain jobs (pretty much anything having to do with what you see on stage - the actors, set builders, and so on). Having their membership listed prominently in Playbill provides an easy way for the unions to make sure that everyone who is supposed to be a member actually is.