Giving them a "tip" so they don't steal your stuff would be idiotic, I hope people don't do this. I only try to tip them because they come by early, they're friendly, they'll come back if I miss them, they don't have the easiest job in the world, you get to know them, etc. As another poster pointed out, a whole variety of people, with the last person being the driver, could have tampered with the package.

-yawkaw