Larry Jaques wrote:

My favorite fantasy is a vaporizing laser system on both borders.
No fuss, no muss, no burial fees, no transportation fees, no legal
fees, just a big puff of smoke as you're instantly toasted. The perp's
minerals will enrich the ground they drop to.

Douglas McArthur suggested a five-mile radioactive swath between the two
Koreas.

At the least if would make killing the infiltrators easier since they'd glow
in the dark.