As the Robbo was parked in a strong wind situation at a fuel pump, why didn't he tie the blades down? Even if he was only going to be 20 mins or whatever, good airmanship with a teetering head would suggest tying down was required. Having said that the Gazelle pilot should have noticed that and landed further away. I'm sure FL would have a field day apportioning blame.
Over here some years ago, a 206L landed on a pontoon designed to take two 206s with the first one having it's blades tied. The 206L pilot saw the blades were fore and aft and duly landed. The blades weren't tied, turned, intermeshed and the 206L transmission entered the cabin and killed a passenger. The 206 pilot, who was in the crew room, was duly charged with manslaughter and spent well over a year before the case was reduced.
So tie your blades down if you are going walkabout!!