Do You Have to Sweeten the Laughter?

I was never in the sweetening room but there were magicians who, there was a guy who had a machine, the laugh machine. I'm sure he had buttons, hes like a typewriter. And he would laugh along with the show. Itod be a little minor joke, and you go, a ha, not abigger ton. Ha ha, ha, haha. That means that if you're doing a pickup shot later in the evening, which is, i think, usually after the audience has gone home, do you then have to do what they call sweet the laughter?