The saying is, "you can't prove a negative" - mostly true, but really the issue is that with such a wide open future of possibilities for AI and safe (or unsafe) outcomes, there's an empirical issue of it being very hard or impossible to disprove things that are still hidden (haven't happened yet). Humans are maximizers in that we try to spend the least amount of effort when we're not sure what will happen, but after something bad happens, we'll act quickly to address that specific issue. It'll probably take a lot of small and large issues to happen for people to build up their societal "safety protocol" around the technology over time.