Isn't the goal to be in a position that is stable enough you could let go of the outside bar mid-corner?
So.. yes. The ability to let go of a bar mid corner means you are light on the bars aka you arent supporting yourself with your hands/arms. They probably told you that so you would be light on the bars. But to be light on the bars you must engage your core. A great thing that Dan told me after going through YCRS was "pull the tank into the ground with your outside leg." That is much easier to think about and actually execute than "be light on the bars". What pulling the tank into the ground mid corner does is makes you use your legs and it automatically engages your core thus making you lighter on the bars because your core is working to hold you in position as well as your lower body which leaves you light on the bars. It gives you more feeling, helps prevent unintended inputs into the bars, - and yes if you feel confident you could take a hand off (I wouldn't suggest it tho).
Looking at his right arm.. it is 90⁰ to the bar. That is an awful lot of leverage. Straight across the tank is more parallel, thus reducing force and total available travel. A straight arm can't get straighter. That bent elbow can punch a hole right through his available traction.
He is already past the point of where you really need a ton of leverage (which would be turn in). Leverage really comes into play in rapid back-to-back corners where you are flipping the bike from side to side in a quick fashion. Also a factor: he looks like he is using stock clip-ons at a somewhat stock angle. My clipons are pushed as far forward as I could without hitting my levers when steering in the paddock/ moving the bike around. That provides a lot of leverage and forces the outside hand out a little more which would automatically start straitening that other arm I think. My buddy that's been riding on track longer than I have but with stock clipons/angle just moved his out last weekend and said it made a world of difference.
Power has probably been sold out. There wont be any pavement to park on, so if he doesnt mind parking in the grass there should be space. Make sure to buy your camping and spectator passes. If you see me zoom'n around give me a shout! I'll see if I can find that monster out in the camping area and stop by.