I was thinking about this the other day. I have a team with no seniors at all, so I was debating on who I wanted to be my captain. I actually have a sophomore and a freshman who are more team leaders than the 6 juniors I have, but I can't in all good conscience do that, can I?
I would think for the high school level, that it would be up to the coach to decide which ladies are captains. You might get elected someone who doesn't want it or who doesn't deserve it.