How many times have you tripped on a step because you didn't notice the "Mind Your Step" sign? And how many times was that due to the fact that the "Mind Your Step" sign was posted on the step itself, instead of at eye level, where you were most likely to be looking?

Similarly, I wonder how many people notice this sign for the first time when they're inches from the ground, with their feet in mid-air and their arms flailing at their sides. "Oh! It's a slippery pathway! That's why I'm falling!"