Thanks, Silly Puppy and Columpuss
Thanks, guys, for your feedback. You both are right, of course:
Silly Puppy: You're right; there are a lot of scams out there, especially in a poor country. Even while I was giving this gal some extra money, I knew in the back of my mind that maybe I was being really foolish. But what the heck, I felt that I was doing something right, and so I decided to stick with my instincts.
Columpuss: Thanks for the really great suggestion about the lottery tickets. A lot of these folks in the city are genuinely poor -- and a lot of them are families of former South Vietnamese Army soldiers who were not allowed by the new regime after 1975 to get decent jobs or even send their kids to university. They're mostly living day to day. If I can help out a little, I'd feel less guilty.