When I queue up with friends, I expect to play by their side. Whether we're conquesting new objectives, defending our assets, running a flag, or retaking lost towers, two or three people dedicated to working together stand a better chance than one person alone. When I wear the battleground crown, I make sure that whoever I came in with is in my group. I also answer other people's requests to be placed with their friends. Those groups are likely to be fighting side-by-side.
When someone else is not the leader of the battleground, it can be exceptionally difficult to be transferred among groups. This is not like saving a spot at the lunch table for a friend, but it's about winning the game. I've been playing Paladin lately, but I usually play Shaman. As it stands now, only people in my group can receive the benefit of my Auras and Totems. This may be changing in the future, when some of these buffs will affect the entire raid. For now it just makes sense to honor these requests. If the players have a working synergy, the entire team does benefit from placing them together.
How do you handle grouping in the battlegrounds?