No friend required if you are not careful about the biome you waterladder your way down.
*stream of water suddenly vanishes* What? *Looks up, notices ice block laughing at the inexorably and slowly falling steve...*
BTW, thats also an awesome way to die in your cobble gen. I always get "into" the forming cobble block a little bit to minimize the chances of cobble burning up.
One time i set my auto clicker (rubberband) on my mouse, and a few seconds later i heard the death sound, the water turned to ice, and the cobble never formed.
if you can get a vacuum hopper that will stop the loss of cobble
though that requires some luck with endermen