Yes, there is no proof either recent or ancient which even the most died in the wool deviate who has been hoaxed into believing in alien intervention can argue against me. But I am not convinced there is no contact dimensionally or via spiritual cognition. Of course if I had such an experience I would wonder about the origin and check my Kool-Aid if anyone was around that day. There are UFOs and they are man made or secret developments.
Here is a British official take on the matter. Do I think people who believe will change their minds? That would be stupid for me to expect, I would hope they put their energy into something constructive and start learning - but it is not likely for most of those with illnesses or issues which brought their visions in the first place. In fact it might even make them unhappy and less well-adapted.