J.R. Goudeau:
Without long-standing relationships, divided by race and socioeconomics and even age, it's very difficult for a short-term mission trip to avoid the trap of poverty tourism. The point should not, should never be, enlightenment for the privileged on the backs of the poor they came to serve. ... Difficult, but not impossible.
This is a very thoughtful post backed by personal experience. I do think that short-term mission trips can be a very good thing, but those embarking on such trips should be mindful of these thoughts.