Good idea, but way too public. Find the motherships (easy with satellites.) Then one per night, have an a/c from a carrier in the area launch Harpoons at them. Do it from beyond visual range, at night. 2 missiles in the initial hit, then 2 more a minute apart. All there would be in the morning would be sunken wreckage and some flotsam.
Even better. Use some 2000 lbs laser-guided bombs. No announcements, just the mother ships disappearing one at a time over a month. Total denyability and they would get the message very quickly.
Trouble is . . .
From OThuga’s perspective . . .
that’s far too sane
and far, far, far tooooo sensible and patriotic.