The question isn't how it's can and no.
you have to get in a modded lobby
Modern Warfare 3 hasn't been hacked yet. Wait a couple of years.
get a lobby and challendge it to a duel, if you happen to beat the lobby you just have created a challedge lobby
Get into a challenge lobby.
HACKERS
challenge lobby
For hacked lobby my fc is 133366403983
yes
Have someone invite you to one.
Yes!
Unless you are in a modded lobby...you cant.
Millions, It's so easy to find a lobby