Phew, glad I asked ! When I detach, it works fine. But as noted above, it leaves for a very time consuming 180 degree scan cycle.
It used to work much better (servo did not make as much noise) earlier on in my project, but seems to have gotten worse. I have added other circuits since then that draws a little more power, but wouldn't think it to be that much (the only active power draw is a Parallax sound impact sensor, which is a 5v part but spec doesn't list mA draw); other circuitry a push button and led, neither drawing power in this scenario).
If I can figure out why I have to delay 700mS before detaching and figure out how to get around that, the detach() solution would work very nicely.