If I see something rated R, forget it. Any interest in it abruptly disappears.
If it's rated PG-13, eh... it's kinda iffy, but I probably wouldn't see it.
If it's rated PG, oh, sure, I could watch it.
If it's rated G, it'll porbably bore me. But at least I know there's no sex/cursing/violence.
And none of these are parent-imposed, they're my own preferences.