I'm sure people do it and don't post on YouTube. In fact, people have been doing it for years before there was a YouTube. Some people don't get away with it, but most do. It's a myth that there are no old, bold pilots.
Around here, no need to even find a creek bed. Just go up in the mountains and tuck a wingtip into the rising lift side of a canyon to get your jollies of being inches from death on, if that's your thing.
The glider pilots out of Boulder do it every ridge lift flight, too.
If all you're looking for is low-level feelings of speed, there's ample opportunity around here to accomplish that and even have a semi-rational reason for doing so.
Poor video guy has the disadvantage of living where it's flat, so PoA folks who've never flown fast in the proximity of Terra Firma, can claim he's "unsafe".
I mean, yeah, in relationship to the fact that he doesn't HAVE to be that low for what he's doing, I get it. But none of us have to go aloft at all, either.
That's the end game of over-regulation. No flight allowed without a purpose deemed appropriate to the regulators. We already see it in the Private /Commercial "common purpose" rules and we all know people have flown folks places they had no real common purpose to go to.
Hell, even if I fly my wife to Vegas, she's going for the food and maybe a little shopping and pool drinks, and I'm going to lose a few bucks at a craps table. We don't have a true common purpose. LOL. If I get lucky, I'll cover whatever she buys. Haha.
Lawyers don't like it when you say your common purpose was "fun" and aren't specific. Heh.