If I recall, it was a bit more elaborate than that. One of the three seals was obvious and easy to restore (the paper between the door and wall). If all three were broken, it meant an unsophisticated intruder was in the room (e.g. his family members). If one of the seals was restored and the other two were broken, then it was a sophisticated intruder instead (e.g. the police).

IIRC Snowden said he used similar tricks to see if his hotel room had been searched. One was a cup of water behind the door, that would be knocked onto a tissue that he'd sketched a hard-to-reproduce drawing onto. I think he mentioned another method that I've forgotten, but the pencil lead trick sounds familiar, so that could have been it

He was also known to be into anime, so he could well have seen that scene too

I learned 2 out of 3 of these (possibly I forgot #3) from a kid book in 'how to become a spy' which I borrowed from the local library. I wasn't into literature but into informational books. I was eating all these books like crazy. There were loads of tricks in this one, including writing with milk and using lemon to make it appear. Shoe lace tricks were also there. Techniques on how to follow someone. This was at the very end of Cold War, begin 90s.

There's good podcasts out there about PIs, spies, military intelligence, and good ol' police work. So I still love the content. The last one I finished was yesterday, about the murder of Dutch politician Pim Fortuyn. The murderer, who was pretty much caught red handed, was curiously living next to a former top criminal which was omitted from the police report to protect this person against public outcry. This person a few years later happened to live near an Islamic terrorist. So the question arose if the former top criminal gave the weapon to the murderer, or whether he was an informant for the AIVD (back then BVD). Of course, the former top criminal passed away whilst the podcast was being made (classic plot twist). Regardless, a fascinating story, albeit inconclusive.

I encountered the hair trick on Ren and Stimpy...Ren's first chest hair was taped across a door or lid to show if it had been opened. Not sure why, but that left an impression on me.

I've encountered the hair trick before, which is similar

I was like "what's the hair security trick?", then proceeded to learn how tricky it is to Google for anything hair + security related, because it's flooded by wig securing techniques..

> Close your door and stick a single hair across the gap - so you will know if anyone went in.

Now your comment comes up in the first page

Haha, that is funny. Thanks for the alert :)

And this is why the new search engines like perplexity and searchgpt are going to eat google's lunch.

The hair trick can be used both by good guys and by bad guys. Recently in my country in the first page of the main newspaper it was explained that during the vacation period, people would do the hair trick on house and apartment doors, they'd then come back a few days later, in the middle of the week: if the hair is still there, then the probability that nobody shall come while they're stealing stuff inside the apartment is much bigger.

> The hair trick can be used both by good guys and by bad guys.

Duh.

Are you implying the existense of opsec-techniques that are only usably by "good guys"...?

It's funny but many people operate under this illusion that criminals don't read, or that they can only read step by step instructions that are labeled "FOR CRIME". Even laws get passed under this illusion.

I think the point is that it's used differently for criminals. The intent was to judge traffic, rather than make sure nobody tried to break in.

I was honestly surprised, that is pretty cool! Some creative ideas and very clearly explained and illustrated.