The few in the beginning may not get warning, but if they do it on a large scale, there is going to be push back and resistance. What is always quoted - 80 million gun owners? They won’t even be able to put a scratch in that number.
Besides, Obama’s signature on a treaty is Unconstitutional without Senate approval, and even with Senate approval no treaty can usurp a very understood US Constitutional right. And moreover, the next reasonable president would just withdrawal from any silly UN gun control treaty.
Some think the idea is the police will come door to door to take guns if all this UN crap passes. I think that would be just about impossible with as many guns that are in the USA. But what if this BS UN anti-gun stuff went through and a law was passed stating it’s a felony to have a gun, lets say they slap you with 10 years mandatory jail time. There would be little need to go door to door, no big fight then. That alone would scare many into handing over their gun(s). If a person was brave enough to hold out and keep their guns, what would they use them for? If caught using one in a self defense posture let alone target practice, instant 10 years prison time. Im just making up this 10 year sentence, but “what if” they did something like that ? The whole idea of this with the UN scares me.