Do people really expect parents to watch their kids every second?

Every time I hear stories of a kid drowning in a pool or getting injured, you hear the parent say, “I just looked away for a second; he was fine when I last checked.” Then you see people always respond, “That’s why you have to always be watching kids.” Do people really expect parents or babysitters to literally not take their eyes off kids at all? That’s insane to me, especially in public where there are a bunch of distractions.