I see no reason why Mr. Pennell should not go picnicking.
5 seconds sound clip from the She Wore a Yellow Ribbon movie soundboard.
You can hear this line at 00:11:14.016 in the Blu-ray version of the movie.
Quote context
[...]
- Sir, I have denied Mr. Pennell permission to leave the post.
- And for what purpose did you wish to leave the post?
- Picnicking? Picnicking? Where, in St. Louis?
- Oh, no, sir, just out by the waterfall.
- Never apologize, mister. It's a sign of weakness.
- I see no reason why Mr. Pennell should not go picnicking.
- Thank you, Captain Brittles.
- So, may I escort you to your quarters?
[...]