A single button labeled "Murder" appears out of nowhere appears, and if more than the majority of people press it, then the people who didn't press will die.

I'm pretty sure most people would just ignore and keep going with their day since why would everyone in the world be so cheesed to press the murder button?

Anyways, these are all reductive scenarios once outside of game theoretics (like this one partially is) - I find this ragebait question really funny because every minor reframing shows significant biases in how you map the theory of mind for the public, and makes the reductive question entirely different.