The project surfaced on r/sanfrancisco recently, where the owner laid out the problem with the blunt arithmetic of someone who has swept up a lot of safety glass. Three break-ins in two years. A laptop gone, a child's device gone, a bag gone. The usual advice — take everything with you — collides, as they noted, with the reality of daily city life: you can't haul everything into every errand.

The response from the thread was uneven but instructive. One commenter offered the practical warning that any visible box is still a target, which is the essential paradox of the whole enterprise: concealment is the actual security layer, not the steel. Another shifted the concern entirely — as a former Prius driver, they'd be more worried about the catalytic converter, a theft problem that no lockbox addresses. Someone else flagged that car break-in numbers have reportedly dropped, and asked when and where the last incident happened, a reasonable question in a conversation that tends to outpace the data.

What the thread didn't settle is whether a DIY lockbox actually closes the gap — whether the effort of fabrication and installation outruns the risk of, essentially, advertising that something worth locking is inside.

But the owner isn't positioning this as a product or a policy. It's a person with a drill and a recurring problem, trying to reclaim some ordinary use of their car.

If the box gets built and installed, what someone walking past that Prius would notice is nothing at all — which is, more or less, the point.