A Haunted Swing in Firmat, Argentina?

Firmat, a quiet city in Argentina has recently come under media spotlight and gathered quite a following on YouTube. A swing on the children's playground started swinging on its own as we can see in the video below. Note that one person stops the swing but after a short while it slowly starts swinging again while the other two next to it stay still.

Then someone had an idea to remove that "haunted" middle swing. It didn't change much. Now the swing next to it got "haunted". You can see it here:

Some time later, they replaced the middle swing with a new one. No prizes for guessing what happened. Even those who don't speak Spanish might figure out what the words in the opening of the movie mean.

"La nueva Hamaca se mueve".