This is almost certainly “apple privilege” (since 3rd party devs would not be able to do such a hack at the OS level prior to app launch) and them preloading the camera so that the time to take a picture from tapping the icon is as minimal as possible

Huh, I just tried it now and the green light does flash for a second. I haven’t noticed until now. With its current position on my screen, the only chance it could happen is when I pull down the control center from the top right corner. I tried it several times and even deliberately slid my finger across the camera app. It didn’t activate the camera. So as long as the camera icon isn’t the first thing you touch, it shouldn’t be an issue.

Isn’t this a part of a larger iOS problem where swipes often register as taps? I frequently have widgets think they were tapped on or ads open up in apps because I scrolled by with my finger resting on them