This may well be true in the US, but not here. If someone wants to - say - suddenly cross the path because they've seen some wild flowers, they can do so. Without looking. If some dick (yes, Locker, I'm talking about you) rides into them because he's hammering along on his bike, going far too fast to stop, then the cyclist, not the pedestrian, is absolutely at fault. Just as motor vehicles have a responsibility on the roads to make some allowances for wobbly cyclists (it's in our highway code somewhere) because motor vehicles bring the danger to the highway environment, so too do cyclists have a responsibility to allow for pedestrians zig zagging about the place, because cylists bring the danger to the shared path environment. Pedestrians are under no obligation to check blind spots, indicate or anything else before they move around the path, which is how it should be.