Most safety switches on firearms expose a red dot meaning the weapon is "ON"/ready to fire.

In electrical industry, red used to mean powered or hot or dangerous, green unpowered or harmless.

All earth-leakage breakers in my area are like this: https://en.m.wikipedia.org/wiki/File:Schneider_Electric_A9D3... https://i.ebayimg.com/images/g/sHYAAOSwu2ZkBk5~/s-l960.webp

Electronics industry have diverged.

In security red generally means encryption/protection is active.

And then there is this: https://en.wikipedia.org/wiki/Tally_light

> In the active (on air) mode, tally lights are typically red.

> Some cameras and video switchers are capable of additionally showing a preview tally signal (typically green) for when the camera is about to be switched to and become the main source of video signal. Once the switch happens, green changes to red.

red and green should not be used like that. A significant fraction of the population, especially males, has difficulty telling them apart.

That's why mains wiring no longer uses red to mean live and green to mean ground.

I’ve seen it a few times on the web with cookie preferences pop-ups, to set your tracking and personalization preferences. Dark patterns to confuse and trick website visitors into enabling all tracking settings.