Not saying you're lying dude, just saying they don't do that anymore around here.
Not saying they don't go below 500 ft either but there's a huge difference between a few hundred feet and the 10-15 ft at 40 secs into the OP's vid. I've got T-6s in the backyard all the time but they don't drop down below the tree line on 515 either. That would be nuts.
There's flying tactical and then there's screwing around with your aircraft. Unfortunately for me, been there, done that, got my pee pee slapped. Like this guy...
In the 80's we were at 300' AGL in C-130E's, on low level training routes. Our wingspan was 156', if I recall, and I do remeber us climbing just a bit a few times, to turn. OCONUS, with some threats possible, lower than 300' wasn't uncommon.