While the tactics you mentioned are valid, I'd still say that the k/d ratio is not important to the team at all.

I just don't think snipers contribute much except for a couple of situations. One is when you have the enemy has been beaten down and reduced to only infantry units. The other would be to take out engineers repairing vehicles. But it bothers me to see one of my team's buildings destroyed while there are 3 or 4 snipers on our team out shooting anything that moves rather than back defending or repairing our base.

Still it is fun to sneak up behind one and put a clip fun of pistol rounds directly into their head or a C4 to the head. There's just something about watching someone run around with a timed C4 stuck on their head that entertains me.