Vast majority of hood-fly-ups that I've seen on the forums, or FB have been with an aftermarket hood. I'd say 99% or so. I actually do not recall seeing anyone with an OEM hood and OEM hood latch and safety catch in place ever comment on their hood flying up. I'm sure it has happened, which is why I left 1% our of my tally, but I don't recall seeing it much.
Anytime i close my hood, i grab it with both hands and lift the car up with all my might. It's a habit at this point, even when I walk around the car to check the hood. My hood setup is all stock though, and avoiding a fly-up is one reason why i've never changed it.