<the short>
If there's any debate about it, I have evidence that incorrect spoke
line does not correct itself in a tensioned wheel.
<the long>
I recall there being some debate around here about adjusting spoke
like. It seemed like there was some question about the spoke line
"fixing" itself to be straight when under tension, and that the
internal stress was a myth. Since learning about adjusting the spoke
line, I've held the belief that it is an important part of the
wheelbuilding process.
For what it's worth, last night, I retensioned one of the wheels I
built myself in the past. I had built it without adjusting the spoke
line (I wasn't familiar with the technique at the time). When I
detensioned just two full turns all the way around, the outbound spoke
arced out of the flange back toward the rim. The spoke line had not
adjusted itself, which is no surprise to me.
I pushed the spokes into a good line with my thumb and retensioned the
wheel.
This was a wheel that probably only had 30 hours on it -- a single
speed MTB rear (symmetrical spoke lengths).