Looking at the video again, it went upside down so fast that it had to be more than just brakes locked. Like the PIC says, "something happened" and I call it pilot error. Even with brakes locked if he touched down smoothly the tires would have been more likely to slide and burn off a hundred landings before it went upside down. If he had forward stick at the same time ala "nail it to the runway" chances are much better that it could have been the extra to cause the momentum shift forward and BAM.
Good example was a pilot I flew with in Colorado years ago. Crop duster with thousands of hours in Stearmans. He wanted to show me some fields to spray using our little Bellanca Scout (that we used for training) and he made some serious pilotage errors applicable to the Scout. When we got back to his 4K dirt strip, he was frustrated at his basic flying errors and when we touched down, we bounced. Before I could say "DON"T", he DID and shoved the stick forward sticking the prop about 4" into the hard dirt causing it to bend and set up a hard vibration. It was a not uncommon technique for Stearmans and many other tailwheel aircraft. The problem is how much forward stick to use and carefully it is applied.
No matter, the guy screwed up just like the DCA guy did. BTW, are there any other pilots on the forum who have more than a few hours in the SJB (C-45, D-18, Twin Beech)?
Always enjoyed flying them and thought they were a pussy cat like the R4D/DC3.