Some of the paneling on the side of the hot tub was coming loose at the bottom. It was the result of the material crumbling around the staples holding it. They were put in at an angle, so there wasn't a lot of material actually being held.
The staple has been removed, but you can see where it was.
After an extended search, I was able to find stainless steel finish nails (thank you Lowe's; bite me Home Depot). With very few nails I was able to secure all the loose paneling, and it is nearly impossible to tell anything was ever wrong.