We have several codes for incidents in camp:

Stray cat: Intruder/Unauthorized Person
Campfire in ____: Fire emergency
Harry Potter: Lightning
Semi Trucks (We're right off the highway): Thunder
Missing package/mail: Missing person
Honey: Bee/wasp/hornet nest
Making phone calls: Using the restroom

They're not TOO cryptic, so they're easier to remember in case of a real emergency, but they can tip off the staff before the campers catch wind of what's happening (or before the camp siren goes off).