> she didn't know what it was and was concerned it might be a bomb. Given that someone has attached a device to your car without informing you of the intent of that device I think it's perfectly fair to destroy the device

Fair? Yes. It's 100% fair as far as I'm concerned.

But rational? If I thought I found a bomb, I'd be running as fast as I could from it, then once I was a hundred meters away at least, I'd call the bomb squad. Trying to destroy the bomb myself sounds like a momentously stupid idea for a number of reasons. Foremost being, what if this homemade bomb with potentially unstable explosives goes off in my face? Or what if it's remote controlled and the bombman pulls the trigger once I start messing with it? Or what if I successfully destroy the bomb myself.... what do I tell the cops and my neighbors? That I blew up a bomb but it wasn't my bomb? How many weeks would I spend in jail before my lawyer manages to convince everybody that I didn't make the bomb I blew up and for some reason I never thought to call the bomb squad? I think an unlucky man might end up in prison for many years if he did that.