This a simple way of getting unlimited care packages. Make sure you have Care Package enabled as one of your killstreaks. This also works with Sentry Guns and Emergency Airdrops.
  1. Get a Care Package
  2. Go to a ledge that comes up with the option to hit the "A" button to climb up it.
  3. Make sure you have your primary out, then switch over to your Care Package.
  4. Press "A" and climb up the ledge. As you are climbing it, hit right on the D-Pad four times. (You should have your Care Package out again.)
  5. Throw the Care Package and make sure to get it. When you get it, use it. After using it, you should have another Care Package. Just repeat and you'll get them easily.
I don't think you can go into a single game of Domination, Demolition, or Ground War without someone do this glitch. What's worse is that if someone has an Emergency Airdrop, they spam the shit out of the map with Care Packages...