Going into a tribal territory and showing off advanced technology whilst proclaiming your God made you is a method that unfortunately usually wins. As the old quote goes: 'Suitably advanced technology is indistinguishable from magic.'. Or in this case, indistinguishable from divine intervention.
This, unfortunately, is an act that I find quite loathsome. I've mentioned this in an another thread, but I have friends who do go on various "mission" trips providing "humanitarian relief". I appreciate that much of their concern is genuine and well-meant.
However, what really makes me want to puke, is that they never explain that the technological interventions that they bring with them, work whether one believes in them or not. Instead, they "allow" uneducated and superstitious people to compare and contrast the efficacy of their beliefs and deities with that of the Christian faith.
In doing so, those on a so-called mission trip can claim that they did not go with the primary purpose of proselytizing. Invariably, though, they tell me that they are happy to "share" their faith and their beliefs with these other people and that it would be wrong not to explain what Christians believe if they are asked to do so. Bible reading and prayer sessions invariably follow. All, of course, in response to an educationally-disadvantaged individual's queries, possibly made out of respect or courtesy.
It's an powerful psychological technique for which these recipients of their aid are already cognitively primed to accept, and for which they likely have no defence. Hence, it's something that I find morally repugnant to the point of disgust.