It's a secure as you, the user makes it.

You volunteer information about yourself, in a bid to reunite items with owners. If you lose your house or car keys, and then are daft enough to tell the world where you live...!!! THAT'S YOUR PROBLEM. Not ours!

There are warnings about doing this in various areas on the site. We can try to make things fool proof: We can't make them IDIOT proof.