[edit] the camera angle and the camera height from the ground is different as well between the lift off and landing.
It makes more sense than someone going out and grabbing them during the short flight. Those things would need to be sturdy and attached to not melt or blow away during the launch, and they would be hot.
edit: If you open up the first image on the submission and look to the left of the crane, you can see what look like the risers. They do seem to come out of the ground. You can see the same trees as the landing shot.
edit: I didn't realize the page had more videos under the Download button. I was wrong about the rectangles, but you can definitely see it's landing in a different spot in the onboard video (#3). You can still see the risers when it lands.