A counter-action to successful Super Spy Deluxe. When the friendly code is changed successfully, and the planet has at least 30 defense posts, it can sacrifice 10 of them to pop all ships in orbit out of cloak: in particular, the Super Spyers. This chance is normally 20%, except when the friendly code was changed to one starting with mf (universal minefield friendly code); there, the chance is 100%. This is an automatic response of the planetary defense systems; there's nothing you can do to force or prevent this.