In the latest Economist Technology Quarterly, there's a story about a SUNY researcher who is creating an RFID and metal detector system for rangers identify potential poachers walking the elephant trails in Nouabale-Ndoki National Park in the Congo. This in itself is somewhat interesting, but what's also interesting is how he's planning to deploy this technology within the local culture. As the Economist article says:
[...] Many people in Congo do believe in magic and Mr Gulick does not propose to disabuse them of the notion. Local people will receive no explanation for the rangers' new powers. That, Mr Gulick hopes, will discourage potential poachers from turning thought into deed.
I find this a little patronizing (NONE of the locals will read any news sources that will describe the system?), but it may be realistic, at least at first. Eventually, people will certainly figure it out, or they will be told, since possessors of black magic--as the rangers will likely be called after a while--rarely like to keep that label outside of fiction. They will do what they can to clarify that no, it's not that they're using dark secrets to do a better job, it's just that they have new tools. But by that point, if it happens, the value of the tools will have been established.