The cheers were scripted.
The script was distributed.
That's not how it is done. There is an applause sign. There is an audience manager that prompts the audience for a reaction. This is usually the same person that does the audience warmup.
The audience is bribed with promises that the most 'vocal' guests will get prizes or recognition. Then, of course, the show is edited. The 'laugh track' is added.
The end result is the same.