Pure bunk. There are things that happen that are strange, odd or seemingly unexplainable. If you believe in demons, then you think these things are evidence, when the reality is there is probably a rational explanation for all of it. It's 10% unusual event, 90% imagination.
Supposedly buying things from garage sales is an open invitation for the demons to attack, but I have been buying things from garage sales for forty years and I have not had one demon attack. I am either the luckiest woman on earth or they just don't exist.
I am not lucky.