Community theatre folks are glad that you came, and they make no pretense about that. They've worked for weeks, mostly after hours and on weekends, in an undertaking that doesn't pay the grocery bills or even the transportation expenses. I'm always touched and honored when players and staff position themselves to greet audience members as they come out of the theatre.
Over decades of diplomatic assignments I regularly shook hands of officials receiving guests at the entrances of embassies for national day celebrations. Here in Austin in contrast, particularly on the periphery, your artist hosts greet you at the end, sending you home with good wishes. They've shed their imaginary world and discarded fictitious characters, so you can commune briefly with them as part of the community of the theatre.
There was no particular protocol in the line after Wait Until Dark. Stephanie Newton, fresh off stage from her appearance as a police officer in the final scene, was the first who shook my hand. My friend Stephen Reynolds, cast as the mostly absent photographer husband of the blind protagonist Susy Hendrix, joked that every night between his scene in Act I and his last-second appearance in Act II he had time to read a novel. For opening night, to top it all, the company observed its tradition of inviting audience members to linger with them around a long table laden with good things to eat.
Wait Until Dark is a perennial. Frederick Knott had already written the successful Dial M for Murder (1952) as well as the script for Alfred Hitchcock's movie. In 1966 his Wait Until Dark with Lee Remick was a huge success, made into an even more successful film starring Audrey Hepburn and Alan Alda. Knott never wrote another play, but the royalties from regular productions of those two playscripts provided him a income sufficient to live a comfortable social life in New York City until his death in 2002.