So, my wife's family has a "no shoes inside the house" rule, what is fine... until you realize that they mean "*no shoes inside the house*" - regardless if you are actually wearing the shoes or if those are in your luggage or something.
So you're supposed to leave all footwear on a shelf on this bench outside their door.
That proved to be tricky when my 10yo twin girls started freaking out that someone was going to steal their prized shoes if we left those outside the house during the night.
It would actually be a risk in our own neighborhood, infested with amazon-package kleptomaniacs, but here we are deep in the country.
Now, I've been to my in-laws place many times, and they absolutely cannot be reasoned with. I wish I could use their stubbornness to train a LLM into relentless compliance with company policy.
So, in order to spare my girls from some of my in-laws paranoia, I've spent some time before we came here rigging up a wifi cam to a facial detection service. (I know I've just exchanged their covid-style paranoia with my own surveillance-state-style paranoia. Those are the times we live in. But i can see the irony)
The server monitors the camera feed and stores the first few seconds before, during and after some face is detected.
I trained a facial rekognition model with our family's faces and had it notify me every time some unknown face appears on camera.
Finally, I've printed a "smile, you are on camera!" sign, taped it over the laces of my tracking boots, and hid the camera (and a powerbank) inside one of the boots.
My daughters were pacified with that solution, my wife laughed out loud with a devilish smile, and my in-laws completely ignored me when I tried to explain it all. Perfect.

The system has been up and running since before christmas. It notified us when some relatives arrived for celebrations and one package delivery - no shoe-related shenanigans. Until this morning.
My daughters have been playing with some neighbor kids, and a couple of those decided to fill their shoes with mud on this new-year morning, as a stupid childish prank.
I know because they kneeled in front of the camera earlier today.
Right when I was finishing up my stretches for the morning... less than 2m away from the door.
The wicked kids looked straight at the camera, and you can actually pinpoint the moment that they realize they have been caught. Then you can see when they hear me unlock the door...
I opened the door to find a bucket full of mud and no soul on sight.
I'm not posting the video, they are minors, after all. But my family is sure to laugh at it every year... and my in-laws will keep on bringing it up with the kids' grandparents forever :)

I was playing with AWS and came across Rekognition! Although the docs are poor, the service is just amazing. Mind blown.

Woo-hoo! Today I built a booby detector using amazon rekognition technology. Let the jokes begin!!!