Assuming that to be a serious question.... All film studios employ security to keep out idiots who come round trying to either get autographs, have a look at what goes on, steal the equipment and the "cuttings" from the editing suites or even the whole film before it is released.
The porn people rented the place, or at least a studio within, to make their movies and that tended to attract a different sort of break-in merchant .... often wearing a long mac.
The studio owners were only too happy to make money renting the space.
Our security guards didn't mind the day shifts (got to meet and greet many stars) but we had a lot of trouble getting them to cover the night shifts as a lot of shady characters in blacked out Mercs would be going in during the night and many were not best pleased to be asked to show identity cards, open car boots for searching etc.
Those movie cameras and lights cost bloody £zillions.
Having security guards reduced the insurance greatly.
