A friend in New Mexico told me about a time he went to visit his mother in her condo. All of the units looked the same, building after building. One time he arrived after a long drive and walked right in the front door, continued into the bathroom and sat down. It wasn't until he started looking at the pictures on the sink that he realized something. This was not his mother's place. 

Sheepishly he walked back out to see an elderly woman with her hands on her hips.

"Excuse me, ma'm. I believe I have the wrong condo. Pardon me." He forced a smile and exited before the lecture about privacy going to the dogs.

Our home in California had an odd feature. The front door opened directly into the master bedroom. As someone who does not always (cough, cough) make my bed, I found this annoying. Add to the fact that many summer nights are hot it seemed stuffy to keep the door closed. Yet privacy is a nice feature of a culture where not everyone sleeps communally, as in Mongolia for instance, so the hinges swung open, and shut and open again. 

Marital privacy is something many people hold sacred. Except when they don't.

While most people would not walk into the bedroom of a stranger at night, culturally is has become completely acceptable to do it with a camera. 

The list of movies that I recommend as marriage friendly holds a line at marital privacy. I do not want to intrude on someone else's bedroom, and chose not to include those that bring the viewer behind doors better left closed.