In City Folk (I can't remember if it was in Wild World too), there were all these signs scattered around town, and whenever a new villager moved in, s/he would move in on one of the signs, and whenever a villager moved out, a sign would replace their house. These signs just had tips on how to play, such as telling you to sell fish you catch to Tom Nook for bells. People most likely miss these signs because in New Leaf villagers move in surprise places and it messes up their paths or flowers. If they had the signs, they would know where the villagers would move and they wouldn't place hybrids or plant trees around it.
When life gives you lemons, make lemonade.
But good luck with that if life doesn't give you sugar or water.
Even though I don't like having a villager come on in and destroy all my hard work, I'm glad there aren't signs in New Leaf. I always felt like they always looked a little... odd. Creepy, even, when I was younger.
Why is it called New Leaf, if the leaf still has a hole in it?