Look at disc 4, title 4 chapter 5 (back at the LM) about 13min 56 sec into the sequence, right after this picture was taken, Jim steps a bit towards Dave , then Scott or Irwin (too fast to recognize which) passes quickly between the camera and the flag and we see a motion on the flag!
It's unlickely steps could have done this; most likely, the PLSS must have grazed the flag, though it seemed the astronaut was closer to the camera than to the flag. But it's true the motion is the same on the entire flag and doesn't show anything like wind, of course.
It's an example that could be needed to debunk the hoaxers.