They stopped busting actual myths like about after the third or fourth episode of the second season. You just have to kind of accept that and watch them do cool stuff. Oh you also have to accept tons of boring-ass build-team filler.
wasn't there a stunt show that did this kind of stuff with real people rather than handle this as a "myth"...reaching. oh and "roll cage" here = one steel bar
Problem is, a lot of urban legends are nonfalsifiable-- there's lots of oddities in the horror tale of The Hook but there's no real way to come up with a testable hypothesis about it.
I'm guessing step one of this mythbusting was calling a stunt coordinator and being told "you can do that, no probelm", but I guess that wouldn't make for good television to confirm it.