Maybe they could write a code to restrict the access to creation of any ships or defense in the shipyard at the moment of an attack. Or prior to 15 or X mins to the attack on that particular planet. Well a simple thought.

It was active awhile ago, you could cancel shipyard queue but they found it exploited to much... but it's is still in the code. Not functional but still there, but as so many have put it's not going to happen. Although it would be nice for a warning system....

in a similer game to this one it did exist it still does...i would love it if it was implemented to this game ..i always type to large a number and end up wasting resources...this should be sent to suggestions