1-Let's start with the most obvious and biggest error: the dog is sitting. While this may not be a problem for a picture of just a dog, it's plain wrong for the context.
2-We've established the dog is sitting, now notice the leash is loose. This is not a problem until you read the explaination for problem 3.
3-Most importantly why is the owner leaning backward as though they are being pulled with a loose leash by a sitting dog?
4-It says dog walk. The dog is not walking. The dog is sitting. And pulling a person. Who is walking.
Wife could NOT stop laughing and saying, "Whoa there doggie, slow down doggie, not so fast-we can't keep up!"
How observant have you been? Have you ever seen this sign, and like me not noticed anything weird?