Gopher gas bombs are far cheaper.
Gopher gassing works because of the confined nature of a burrow. Hamas tunnels are roomier; but the IDF has certainly brainstormed every conceivable way of disposing of Hamas tunnel rodents.
But Hamas, being the moral savages that they are, will next time force Pali children into the tunnels to trip IDF motion sensors with tragic results.
Sure hope our DMZ in Korea is being monitored by that same Israeli tunnel technology.