I have what is probably a unique perspective, and I won't go into a lot of detail.
There was a time in my life when I was out of work in a strange city, with no contacts, no car, and without a place to live. After finding shelter, I found a temp agency that provided day labor to businesses in town. I worked my butt off every day at whatever I was assigned to do, and eventually was asked to come to work for one company full time. It was a barely livable wage, but I continued to work every day as hard as I could and advanced quickly to being a lead person.
My point is this: Most people who stand on street corners with a sign, or approach strangers asking for money, are perfectly capable of doing what I did. If they're fit enough to stand with a sign all day, they're probably fit enough to find a temp agency and do an honest day's work.
I turned my situation around many years ago, and don't have to worry as much as I did then. But where I work now, I see people every day who could beg for money and probably get it--if they wanted to. But they don't. They work, and they usually have a smile on their faces.
I don't have much sympathy for the sign holders. I could have done that, but I chose to do the right thing and work my way out of my situation.
Sorry for rambling on, but if you're approached by someone asking for money, offer to buy them a meal, or some groceries to take home. Maybe bus fare. You'll find out pretty quick what their intentions are.