I am not sure if its just me but i am really tired of establishing a line of sight for a perfect shot, taking the shot, watching my teammate step in front of me, block my bullets, him fail at life, and get both of us killed. This may seem harsh but it refers to teammates and clanmates. I have screamed at many clanmates for blocking my shots.
The other day i threw a care package, died while trying to grab it, and when i respawned went to retrieve it only to be blocked by one teammate and watch the other get it. I am all for team work and sharing but thats just messed up. I'm not saying to allow people to go nuts and mow down your own team; i believe that is kick worthy.. What i am saying is if someone is stupid enough to step in front of you while you're shooting Darwin's Theory of Natural Selection should kick in and allow you to wound that tard.
They don't, at least in MW3 they don't. Your teammate can block your line of fire and many times I've been shooting at someone only to have another guy stand right next to me eating my bullets thus getting us both killed
this didnt happen in cod but i once suicided a rocket launcher by shooting teammate who walked thorough me when i shot.
as for getting in your way, taht is annoying, espicialy in zombies but FF will hurt more than help.