a friend of mine lost control of his miata on a similar road, ran off into the ditch and went through a barbed wire fence similar to this, though the ditch wasn't so steep. thankfully he had the presence of mind to pull himself up against the steering wheel as he went off. because the top was down, the barbed wire rode up the windshield then snapped back down into the cabin. the barbed wire cut the top of his head and he bashed his face on the wheel but the barbed wire SHREDDED the headrests of the car. had he not ducked, he likely would have been decapitated. instead, he just needed a couple of stitches in his scalp, and the car just needed paint on the hood, fenders and windshield frame, and reupholster the seats.
i think this rider was lucky in that the bike is what broke down the barbed wire fence, and not their body.
one other thing i thought was odd about this group - the lead bikes looked to be harleys or similar. how often do you see sport bikes riding together with cruisers? almost never, in my experience.