Guys, I'm in SFO, followed all your advice.
One question, I accidentally tore my SFO-PHL boarding pass that was issued to me in Auckland, so after dropping my luggage at the bag drop for connecting flights at SFO I walked over to the United desk and they reprinted my boarding pass.
However, when they did the lady said I had to say "no luggage" on their online check in system, even though I had dropped 3 bags off at the bag drop area.
She said it wouldnt be an issue, but I'm paranoid my luggage may not be loaded onto my flight!!!
Am I being irrational here?