Seeing this sign, what warning can you make?
"You must take care of dog poop" or "dog poo"?
What's the difference between poop and poo? and can you use this for this sign?
'Poo' is more polite in AusE, I would hazard to opine.
But different families use different words with their children, and the word you grew up wth as a child is probably going to sound less offensive than another term.