Printout (playtest version)
This was a "You had to be there" puzzle. Teams had been told to dress up. Some teams were told to wear dots; some to wear stripes; some to wear solid, no-pattern clothes. In their starting packet was a page that was basically a list of teams. Finding teams, seeing what they wore, translating dot/stripe/solid to dot/dash/space and then reading Morse code yielded NATO ALPHABET CLOTHING.
This happened during registration; it gave teams something to do while waiting for other teams to register. Since teams were encouraged to help each other, new teams who might have otherwise been distracted by red herrings were (mostly) set straight by more experienced teams.
Eventually, the game started: there was a speech and the ClueKeeper start code was revealed so teams could check their answers.
Teams that entered NATO ALPHABET CLOTHING into ClueKeeper were nudged to look at the code sheet in their starter packet.
If you think you know the answer, you can check it here: