The creation and deletion of worm holes happens before ship movement in se4
there fore you can tell the ship to open a worm hole and tell the fleet to move thru to the targetted end of the worm hole, it will show the path going the long way because there is no worm hole yet, but the worm hole is created before the fleet moves and the fleet always chooses the shortest path in this case thru the newly created worm hole.
So you can create and move ships thru the new worm hole in the same turn in similtanious play e.g. in pbw
and yes a facility to be able to stop worm holes being targetted at your system is a good idea, at the moment my only defence against it is to spread my forces and factories out so no one system is of great value to my race.
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CyC
L+++ GdY $!+ Fr+ C--- S* T!- Sf++ Tcp++ A? M++ MpM RV Pw+ Fq++ Nd+++++ Rp++ G