We too, had a Yellow Jacket whisperer on our trip. He would remove the trap with the 300-400 YJ carcasses with a long stick, and dip it in the river before putting it in the trash bag. They really were not that interested in people....only our food.
One of our group was unlucky enough to get stung twice....once in the outhouse at Corn Creek (right in the taint!) And then at lunch, a YJ crawled into his ham sandwich, and he got stung on this tongue. He is, undoubtedly, already mentioned in Yellow Jacket folklore....