I propose a minus 1 danger rating per hour card. This is to help counter the +1 danger rating card. When you get that card played on you- you just have to wait it out and watch all your fleets get huge amounts of danger. Then you watch as they all get attacked. It would be good to have something you can do about it to try to lower your danger rating and counter the attack.
Or it could be a common card that lowers your danger rating for all fleets by a flat amount instead of each hour.
-Captain D