There doesn't seem to be an easy decision here. Every decision is laden with consequences. For example, the neighbors asked to use some laundry soap today.
In the States, I wouldn't think twice - of course you can have some. But here, when you offer things so freely, you set a dangerous precedent for how much you're willing to share your relative opulence. Though I live in a rich neighborhood, and I'm not, there is still the expectation that I have more than enough to give away.
It's quite often that kids will show up saying "Give me X" (because they learned the English "Give me" construction), or "Estou a pedir para..." (which means "I beg you for..."). And though we are not unique in being asked this question, the impetus is our skin color and nationality.
In any case, the answer is usually no, except if it's water. Water is free for us, and to deny water would be inhuman. If the whole neighborhood started asking us for water, I might change my tune, but for now, I'm fine with it.
One of the members of the singing group came up to me, while we were practicing for a performance today. He asked me what nationality I was, and then steered the conversation to war. He had seen US submarines in Maputo during the Vietnam War (when Maputo was called Lourenzo Marques) and we talked about the current situation in Iraq. He spoke about the civil war here, about how it tore families apart, and we came to very similar conclusions on what we wanted most for the world.
Peace
John