But the person who built the device did so with the intention of recording people in private spaces. The person committing the theft did not explicitly consent to being recorded in a private space. They are still being recorded unknowingly by a device designed to do that.

What I'm saying is; the thief broke a law but the person making the recordings could have also broken laws as well. Two wrongs don't make a right, and all that. Just seems like a good gag for YouTube but a bad practice to encourage.

Here's how that would go in court...

Thief: Your honor, this man illegally recorded me in my home without my consent.

Judge: You mean the package you stole recorded you for the purpose of identifying you as the thief?

Thief: ...

Judge: Get the hell out of my court room.

Even in two-party consent states, I can't envision any situation in which a person would actually be punished for recording in this way. Remember that laws are meant to be interpreted by a judge or jury in the context of the alleged crime, not applied to every situation where they can possibly fit.

In fairness to the other side, I think the glitter-in-the-eye part is where an issue might arise. I don't agree that the privacy thing would hold up for shit, but courts have ruled against folks setting up booby traps on their property in the past.

100% agree. Any kind of booby trap that does more than make annoying sounds is a liability, even if it's in your own home. It's also important to note that in two-party consent states the camera footage wouldn't be admissible in court for prosecuting the thieves, so as an actual deterrent that part is pretty low unless you're going for social shaming or something.

This device does not place a hidden camera where people have a reasonable expectation of privacy.

Someone STEALS that device and moves it. The device's owner isn't breaking any law.

You are looking for problems where there are none.