The script for Being There ends as both Peter Sellers and Shirley MacLaine take walks in the wood. They run into each other. She says “I was looking for you, Chance.” He says “I was looking for you too.” They take hands and walk off together.
But near the end of production, somebody went up to Hal and said “How’s it going?”
“Great,” Hal said. “Sellers has created this character that’s so amazing, I could have him walk on water and people would believe it.” Hal stopped and thought. “As a matter of fact, I will have him walk on water.” …
[Ashby] had to deal with keeping the shot a secret. There was this one, very well dressed kid around the set who was officially called a PA, but whom Hal suspected of being the studio spy. Hal called him into his office and read him the riot act.
“I’m going to ask you to make a decision right now that’s going to affect the rest of your life,” he told the kid. “I’m going to ask you to decided whose side you’re on. I know you’ve been watching me because you want to learn how to make movies. I also know you’re watching me to make reports to the studio behind my back. I’m about to change the end of this movie because I’ve come up with a better one. The studio can’t know about it or they’ll shut me down. This is it, kid. Decide. Are you on the side of art or commerce?”
The kid kept his mouth shut. The shot got made. The studio was pissed but they used the shot anyway. Hal didn’t give them a choice. He didn’t even shoot the ending in the script.