The Ströck Bakery reaches around 100,000 customers per day or so. Most of them are confronted with ME/CFS on a daily basis. Using the back of the bread bags as an awareness tool has real throughput. That this works in principle is measurable by the fact that this advertising space can be sold. On the other hand, I doubt most people would believe how little the troughput in terms of actual donations (in terms of advertising per se, in this case buying a specific bread leads to a 50 cent donation through Ströck) is.