You Are Bad Guy - Pretty Boy Floyd

Mr. Robot before the Internet.

And the reason said people were freed from debt is because, back then, the destruction of those mortgage papers would mean the destruction of their mortgage, since the people who use them are probably not capable of remembering the individual mortgages of everyone and digital stuff didn't even exist.

In other words, that shit definitely wouldn't work today, since your mortgage papers would just get printed a couple thousand times after they're destroyed.