For every iPod that iTunes sees, the serial # is RIGHT there. ****, they even know how many computers I have authorized.
But with that said, IMO, by the time someone were to make a police report, the lost / stolen iPod would already be in use by someone else.
It be nice if a stolen iPod would go into some type of locked mode with no way of unlocking unless taken to Apple w/ proof of purchase and ID. But that would only happen in a perfect world.