I'm not an expert, by any means.

IMHO - it is your belief in something that makes it work.

Not in all cases. But hear me out.

If you don't believe in God - how can you invoke him for protection? So it would depend upon your spiritual beliefs - as there are many paths.

My personal beliefs are a eclectic.

I do think people (including children) can open doors and things can use them. I do think unprotected people can be influenced. I especially think people under the influence of drugs or alcohol can attract the attention of lower astral entities.

I protect myself, my family and my home - with various prayers, visualizations, blessings and intention.