It's much easier to attack such a system than to defend it. Attacker only needs a short window of time, so can emit a lot of power. "Smart" gun can't do that, i

It's much easier to attack such a system than to defend it. Attacker only needs a short window of time, so can emit a lot of power. "Smart" gun can't do that, it has to work for years on small battery, so its signal must be weaker by many orders of magnitude.