I can force host to anyone that can mod and make it look legit (not spawn killing, no super high jumps) that's how bungie catches people, by looking at the game viewer and seeing that people are being shot from the heavens or seeing that everyone is dying in the same place. I'll force you host and you take it from there with auto-aim...
No your just retarded bungie catches you by scanning the map tags, in the DLC maps, and comparing those with a list of defaults if any are different you get a MM ban. Its all there cleary in the update file