It's hard on the xbox if they do it too much. They should just sign out and then sign back in.
It does t bother me that people do it unless they r host.
It is exploiting as your KD isn't a real representation of your skill but people with negative w/l should never be host
Dashboarding is not the same as quitting. Dashboarding is when the host doesn't allow the game to migrate, causeing the game to end and giving everyone a loss.
In the last Black Ops, the host always had an advantage, but in MW3, they started trying to make up for this, and usually end up crippling the host under certain circumstances.
Mix this with the growing knowledge of what Dashboarding is, and you start seeing the hosting network fail in epic proportions.