One of the inspirations was about victims ability to recognize their own victimization. I love the thought of product messaging that could help with this ... like Christophe's vision of the Geneva convention printed on corn bags. Maybe a universal human rights statement that could help people recognize when their rights were being violated...?
I see your point -- but I do think a data collection component could be involved here. Large corps like Coca Cola must collect lots of data, and changes in consumer behavior could indeed serve as a signaling mechanism. Could big multinationals be persuaded to allow a group like USAID to access their data?
Your idea reminds me of the iconic "Dr. Bronner" packaging, and how people sometimes buy those products more for the packaging than for the item within...not too many brands can make that claim.
I wonder if this idea could also include some kind of "two-way" communication?
If there are established trade routes and consumers making purchasing decisions within these endangered communities, even during times of conflict, perhaps those consumer's brand/product/packaging choices could function as a signal to the outside world, either implicitly or explicitly.
For instance, several kinds of cola might be marketed with labels of different colors, and the choice of "code orange" packaging by consumers would signal a perceived threat.