Veteran players often try to put them there, but they are difficult to place while running sometimes and it's worse if someone pulls before you can place them. It was changed so that you can't place them while fighting.

You can see at the top of the party list which alliance you are. The typical order is A, B and C go left, middle, right. This is important for tanks, who need to grab their respective boss. I see so many tanks in alliance raids that just don't understand this and tether adds together. It can be important for DPS checks or other mechanics as well.