yeah, so shocked when I saw that one. I personally have been to Mag-aso Falls in Antequera, and I have been up on that rock ledge where the two guys were sitting. There's even a small passageway where you can traverse behind the actual waterfall (which I did).
My condolences to the families of the guys.
I had no idea it could turn into a death trap in a matter of seconds. @_@ But as always, gorges in canyons are potential death traps.