Yes, those stains in the plaza parking lot are exactly what you think they are.
Tape: The stuff should be strong and at least one inch wide. But think compact so it doesn't take up too much space.
Glow Sticks: Particularly the ones that can be made into bracelets and will tie around things. A must for trying to be located by rescuers at night.
Stone Arrowheads: You can pick these up online and with some thread and sticks, make great hunting and defense companions. But a word of caution - be smart about the size of the ones you try and put in your carry-on.
Burn Gel Packet: Burns suck enough, but getting an infection and fevers from them is even worse.
550 Cord: There's always need for a good bit of rope, even more so in an emergency situation. It is suggested that at least 50 feet of the stuff should board the plane with you.