No problem for my daughter, who has her BSA Lifesaving certificate and is an avid WW kayaker . . . but her roommate is from El Paso and had never learned to swim because apparently they have very little water there!
It's a pretty basic test, so they dragged her through it somehow without actually drowning her.
Yeah, we had one or two in our class who had to take the class again. I think fear was the major issue.