Owning any fully auto is just plain stupid regardless. To license it you give the ATF full permission to conduct any surprize search of your property at any time.
This is not true, if you are a class III dealer or manufacturer of Class III items, only then can they search your place of business, or residence if you run it out of your garage.
But, if you own Class III NFA items, they cannot come into your home to inspect or search your residence.