The FBI knew ahead of time that Stone doesn't have private security guarding his home. You can tell this from the way the storm troopers swarmed in.....and by the subsequent absence of any "security guy" being grabbed and led away.
The man is broke, fer cryin' out loud. Private security night and day every day costs an exorbitant amount of money that Roger and his family don't have any more !
Leni
See my # 31, also.
Leni