im sure they have programs to screen the email so they no which ones to read, for example, if your email says 'bill gates' in it bill gates will read it and if he thinks you might be up to something or targeting his company then he sends his teams of crackers to fry your computer, if you target the government then he just hides it away so that when you do something he can sue you for misuse of his services...well at least that swhat i think but ya there are those truly hidden files, they say the only way you can ever truly get rid of a file is to destroy your hard drive(physically, maybe a hammer?)