A few years ago I scrolled Facebook on my phone and suddenly saw a post with a picture from my phone and my heart skipped a beat. It was not a real public post, but a suggestion from fb ala "share this pic with your followers? This is how it will look like".
Immediately removed all permissions, insane to take a photo from my camera roll and do that. Imagine if it was some nsfw picture suddenly being integrated into my feed while scrolling in public or so..