I bet there are people out there outside the US who think that you should protect your safety in a boring computer conference, but you won't ever hear about it. This notion is too fringe and people won't dare say it.
I think you missed my previous point. Angry men with guns being allowed into a boring computer conference (or anywhere else for that matter) is the reason people think they need to protect their own safety in the first place.
Can just imagine a Rust conference, and an argument breaks out over memory management, one guy starts yelling about 'borrowing', starts shooting, someone else yells "you can take my pointers out of my dead cold hands", starts shooting. Pandemonium.