Alastair Smith, print editor of The Stage: “[Once,] the rules may not have been written down, but they were clear and strict … Then along came jukebox musicals that asked you to dance along to a megamix. At Shakespeare’s Globe, actors started engaging with the groundlings. … Next, immersive theatre asked audiences to touch the set, to react to the actors. … Rules of audience engagement vary wildly from one show to the next. And the expectations of what one audience member finds permissible also varies from one person to the next.”