Instead of defying those baseball bat-wielding teens with a mailbox filled with cement, just try and make it way less fun for them.
"The last big storm stole my seat off my lawn mower, so I decide to appease Mother Nature by reusing a grocery store bag over top a pillow. Much more comfy, too!"
Mother Nature would be proud! Although I don't think she's too happy on a count of the fact that you keep beheading all of little grass children every two weeks.