At the South Padre Island Marathon, I saw people waiting up to 30 minutes for the Port-A-Potties.
It reminded me of the lines I first saw at the San Antonio Rock 'N' Roll Marathon. But like the SA RNR, I knew there were other restrooms.
I walked a block over and saw another row of Port-A-Potties with three people waiting in there. There weren't any real lines. We were just waiting to see which of the more than a dozen restrooms would be available first.
I'm still not sure how everyone else didn't see this. You have to drive by both sets of restrooms when heading to the parking area.
So, just a heads up to any marathon/half-marathon participants... look around. There may be a shorter line for restrooms.
(And now with this post, I can better explain to people why I was taking photos of the restroom lines.)