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Yes, but that tactic works only if you know you're going to be
under attack. If the shadows were to materialize in the midst of the
refugee ships, they'd just scatter in every direction. The purpose is
to wipe out all those ships quickly and efficiently...so you start at
the outer fringe, drive everyone inward, and then wipe them all out.
To jump into the middle of them makes it very hard to do this...it's
like herding kittens.

jms