Footage is a theatrical snipe, or ad or notice, stating not to engage in sexual activity, including masturbation, in the theater and that it is against the law to do so in a public space. 

Shows the image of a closed hand with a red line through it. Says that violators, those who break the law, will be asked to leave. The message is from "management." 

Ad seems like it's from the ‘50s or ‘60s based on the background music and style of imagery.