BTW, I should point out that I'm not sure that it's good for the Gazans or the Palestinian cause that you can't stop the tunnels. Weapons-based resistance has mainly been a catastrophe. Dying in acts of non-violent revolt would be a thousand times more effective than dying in acts of suicide bombing. And coming up with new methods of resistance where you don't die would be even better.
In the short term, if weapson smuggling would be entirely shut off, the Gazans would probably get more food fuel and medicine because the impulsions behind the continual shut offs would vanish. The function the weapons now play -- to make the suffering of Gazans impossible to ignore -- would still be there. But it would have to be accomplished through other means.
It wouldn't necessarily make resistance evolve into something non-military. One could easily imagine a world where the walls worked perfectly, and Hamas ended up being replaced with an al-Qaeda type organization that recruited people to attack other countries in the name of the Palestinians as al-Qaeda did in the name of the Caliphate.
So I'm not saying it a technological fix would be necessarily good or necessarily lead to non-military resistance. I'm just saying I can *imagine* this technological solution could be good if it was possible. So I don't mean to sound like I'm celebrating what seems like its impossibility in this particular case.
Michael