I remember about 5 years ago (?) the passenger in the aisle seat across from me had a very large laptop, and was watching Game of Thrones, a then-new show. I had heard of the show but had not actually watched it, and was surprised by some of the explicit scenes that showed up clearly from across the aisle.

Would not want to have a small child sitting where he/she could see that laptop screen. But, I agree that it is difficult for the FAs to police actual passenger misconduct.