I'll probably get in trouble from Transport for London for encouraging beggars, but I gave a pound to a very clever young lady on the tube this morning. Instead of simply asking for money, she walked along the half-empty carriage and placed a slightly crumpled piece of cardboard - about the size of a business card - on the seats, beside each passenger. Of course, you couldn't help but read it. It said "I am poor and look after my two sisters. Your small donation will help us eat and find a warm place to stay. Thank you for your kindness". After proceeding through the carriage again to collect her gifts, she scooped up the cards for re-use.
Yes - I had the same thought - it's quite possibly a made-up sob story. That wasn't why I gave her some money. It was very clever marketing, and it clearly worked well - almost everyone gave her something. She'd spotted a way of persuading people to give money and feel comfortable about it. That's how great marketing works.