Certainly there are more refined options. They're also more expensive and require a higher level of technology. Mines are cheap. For that matter, so are various types of noxious gas, also customarily banned.

Smaller countries looking at a much bigger, vicious neighbor must be concerned with cost -- and also how to continue defending borders after their infrastructure has been flattened.

I don't like the idea of reviving landmines, but I can see why those countries are looking into it.