Folks:
Been away from the 14.1 forum for a little spell, so it was a pleasant surprise to come back & notice there's this jewel of a thread!
I don't like the side-of-the-rack safety simply because the cue ball is "too high." Playing one pocket as much as I do gives a bit of a unique perspective on this kind of safety, in that I can't tell you how many times I've sold out when the corner ball leaked out enough that even if I glued the cue ball to the 8-ball (or any of those balls in that side of the rack closest to the cue ball), the opponent still had a shot at the "leaked out" ball -- in this case, the 14-ball.
If the cue ball were just a bit lower -- say, where that piece of chalk is on the rail -- I'd go for the side-of-the-rack safety in a heartbeat, because the angle is more straight "into" the side of the rack. There is no "diagonal energy" (for lack of a better term) that would otherwise divert down the row of balls, pushing that 14-ball outwards.
Put me in the backscratch camp as well. And I like Dave's (SpiderWebComm's) stance on "Brunswicking" your opponent -- glue the cue ball to the rail if you can. The only caveat is be careful with this, because if the ball you "tick" (or another ball next to it) leaks out, your opponent will have a shot at a "threatening" safety -- meaning, a shot that puts the ball in play on the other side of the rack, limiting your defensive counter-moves because that loose ball is now threatening the majority of the perimeter around the rack.
-Sean
P.S.: yes, I know the Brunswick label is on the other side (head end) of the table. I've always playfully called a weld to the center point on the short rail "Brunswicking" the cue ball.