Could Anyone Actually Stay Hidden In Someone's House?

Yes. There was a case in DC where a psycho ex-girlfriend was living in a judges attic. I tried to find a longer article that would say how long she was up there, but could only find this: http://www.highbeam.com/doc/1P2-25298903.html.

I should look for the book "Bad Ronald". It might answer some questions not addressed in the movie. Ronald would have needed to be very careful to avoid being discovered. If he snored it could have been heard. He also had to be careful about coughing and sneezing. And if he was reading something funny he would have needed to hold in his laughter.

How long would it have taken for the house to be sold after his mother passed away? That could have taken months or even years.

I think now having a house inspected before purchase is almost mandatory. It wasn't in the '70s. But the house would have been inspected for tax assessments. And the town would have kept a record of the number of bathrooms. It effects the value of a home. But I don't know if the town would have shared that information with prospective buyers of the home.

You guys are going to think I'm making this up but I swear it's a true story. Back in the early 1970s my adulterous aunt fell for some beatnik type of guy she met in a club. Even though she had six young daughters she managed to fly the guy out to her house and hid him living in her attic without her husband knowing. Even weirder still, this guy didn't really like my aunt buy was just taking advantage of her. He was actually gay, and then conned my aunt into letting his boyfriend move into the attic to as a "friend." Then one day either the guy or his boyfriend had a seizure in the attic and came crashing down through the ceiling in front of my aunt's husband. The marriage ended soon after that.

There's a couple recent stories - I should google them, I suppose, but one involved a woman who's husband was controlling and abusive and ended up in prison. He was released early, but the prison people didn't tell the woman. The guy ended up breaking into her house and living in the attic, where he would then spy on her.

The other one was a click-bait article, but a couple found a trap door in their house. They opened the door, followed the stairs down, and learned some other guy was living in this secret room. He'd come out at night and steal their food.

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