I've noticed that many do not want help, the smell of booze on their breath and just wanting money gives them away.
I was in college and worked part time at a grocery store pushing in carts. Walked out to the end of the parking lot one day and there was someone standing with a sign "will work for food". I tapped him on the shoulder and pointed to the big huge sign hanging in the store window saying "Now Hiring, All Shifts". You rally can't get much closer to working for food than in a grocery store.