Anyone that travels frequently will invariably run into basic textbook social issues with photography. Most common is the confrontation you may have with people who demand that you pay them to take their pictures. This usually happens in poorer third-world countries or pockets of poverty in developed countries. When money is scarce, any means of income is sought, and tourism is often the best and easiest source for money for the least amount of effort. Although there are the clear economic benefits tourism brings to developing countries, there are also disadvantages that can get out of control, which often go hand in hand with an increase in crime, the erosion of the work ethic, or the reduced perception of the need for education. (The latter two are the basic economic foundations for real productivity growth.) When people ask for payment to get their photos taken, the controversy begins.
Paying for Photography
If you're going to pay to photograph someone, make the most of it. Ideas include: organize a format shoot, bring in other photographers, set up the scene, use props, pose your subjects, and most importantly, shoot a lot of pictures. It's an excellent opportunity for subjects to express themselves, either by their clothing, their belongings, or their surroundings. This may also be your only opportunity to get a really close and personal portrait of someone that would otherwise not give it to you.
When tourists find themselves in such situations, they often feel compelled to "help", and the most immediate reaction is to give money directly to people. Others claim that by paying for such things, you are perpetuating a problem making it harder to solve. I cannot help you with what you may perceive to be an ethical or moral dilemma, but suffice to say that, by the time such a problem exists, it's often a sign that weaker economic conditions and social deterioration has already set in, and opportunity for reversal is nearly moot.
Should you pay to take a picture? Under what conditions? It's not always easy (or possible) to discern when it's appropriate, or if you're contributing to a society's own problems, albeit with the best of intentions. The water gets muddier still when you consider the differences in Western perceptions of payment for services, or our attitudes about helping the needy.