I ran SitRep on EVERY class I had. Only to destroy Portable Nubdars. Don't have a headset so I couldn't really soundwhore. Damn did I get some enjoyment from blowing up Portable Nubdars and taking noobs off their camping MOAB streaks.
To me, the Portable Nubdar completely broke MW3 and changed the way it played. You NEEDED Assassin. It was a must.
Nothing beat blowing up a Portable Nubdar, then hiding in a corner near where it was, seeing the noob come out to check on it, then killing him. Felt so good each and every time.
I always try and shoot down care package helicopters before they drop the crate for this very reason. Also because I imagine it makes people rage pretty hard.
It's also the reason I usually run with CP on, because you actually have a chance of getting K9 or VTOL or whatever after like... 5 kills, or even less on objective games.
Not even gonna lie, when I'm in my party of 3, one guy always has engineer on, so on occasion we'll just all run care packages and have them all re-rolled. It's stupid. You can get 5+ care packages a round easy as hell. Chances of getting something good out of them, especially when they're rerolled? Pretty damn high. They need to just completely take it out.