I don't know about you, but when I see a 12-year old kid, a poorly dressed person, or fake celebrity or cartoon character costume (think Mickey Mouse, but gray fur and rat tail) holding up a poster or sign advertising a business on the side of the road, I am less likely to patronize that business than I otherwise would be.
I just passed a restaurant near my house that has opened in the past three months. There are huge handwritten posters hanging in the front window, they have small yard signs placed all around the small retail center, and now they have two 12-13 year old kids standing along Highway 41 (a very busy and dangerous highway) holding signs letting passerby know they are open.
I won't be going there. If the food was good enough, none of that would be necessary.