Also, remember that as long as you check-in, you have your boarding assignment. You do not have to print out your boarding passes right away.
We always check-in via our cell phones through Southwest Mobile. Last time I did it while standing at the Mummy.
Then, when we do curbside check-in for our bags, Southwest just prints us our boarding passes at that time. You won't lose your place in the boarding queue. An added bonus is that you get the nice small boarding passes rather than having to drag 8x11 pieces of paper around.