I understand if the penny is heads up then you will have good luck that day,
if the penny is tails up then you pick it up at your own risk, good luck yes or no.
who knows, I grew up a poor kid, if I found a penny or nickel on the ground, I was a rich kid that day and could buy at least one piece of bubble gun the next time I got to go to town.
I do not know if my grandkids would pick up a $5 bill. times, they are a changing, but hey, I will still pick up a penny as long as I can.