That's pretty cool DM. I've never heard of flag societies, but I love the concept.
They are organizations that promot science, exploration and adventure. The flags are traditions which National Geographic does as well. I is quite interesting.
Here is a link to the Explorers Club: www.explorers.org. The Chicago Adventurers Club site is down right now.
Here are examples that I could find.
Adventurers Club Flag and club lounge:
Explorers Club Flag:
To me, this coin is the equivalent to carrying the flag, only on a more private level.
JYD #13!!! "Nobody knocks off an old man in my neighborhood and gets away with it." - The Burbs