[gh02t]

Most of warhead verification is actually verifying a given weapon IS a real weapon (without giving away its internal design, which is the hard part), not that something is not a weapon because generally you're trying to keep an account of how many/where warheads are. Verifying a given missile isn't nuclear tipped is largely a non-issue at least in the current arms control regimes.

This method has no real way to identify materials, which is what you really need for warhead verification. It would be easily fooled by replacing a warhead with a dummy source, which is a big no-no because now there is a potential hole in the bookkeeping. Weapons grade material isn't actually that radioactive anyway; warheads aren't inert but measuring radiation from them is fairly challenging. Probably not hot enough to see easily with this laser approach, though I'm only speculating on that.