Just out of curiosity, do you know how that interacts with indecency laws? Like for example if someone is having sex in their home but someone is able to see it from the sidewalk through a crack in the curtains? This is purely hypothetical of course.
My understanding is that it comes down to a "reasonable person" doctrine - i.e. would a reasonable person consider the location to be private.
Another way of thinking about it is if there is a reasonable chance that you will be seen by people engaging in normal everyday activities.
Personally, I would say that peeking through a small gap in the curtains would not qualify as normal behavior. Someone doing that is clearly snooping.
On the other end of the spectrum, having sex in front of a window that fronts a public sidewalk with no curtains would pretty clearly be public indecency.
