C'mon guys lets get a reall informative Controlled delivery thread going here.
Well I recently started seeing this lady who turns out to be married....TO A POSTAL INSPECTOR.

Whenever we go out she was always so paranoid, come to find out her hubby is a member of the local FBI who does the controlled deliveries on domestic packages. So of course I rode her for all the info I could get on how the controlled deliveries are performed.
She said things that flag a package are:
*No return address
*Leaks
*Smells
If a package is flagged they will often open it, document the contents, reseal and get ready to bust your a$$.
Heres how it goes down: She said the boys gear up (insert a scene from the movie s.w.a.t.) then will make a peliminary trip around your place (or place of delivery) Now she also said here's what you need to watch for:
*Any one other than your regular postman delivering the package.
*ringing of the door bell, I've had a few packages delivered and my mail man never rings or knocks just leaves it by the door or on the porch.
*And of course and extra vehicles that aren't normally parked on your block.
Normally what they'll do is attempt face to face delivery by having you sign (NEVER HAVE YOUR SOURCE SEND A PACKAGE YOU MUST SIGN FOR) then once you accept it. The door is broken down, your cuffed, house is searched, then the interrogation begins. They'll first guage you prior record then try to massage you into a deal (turn you into a snitch) From there you can either talk and negotiate a lesser sentence or what she recomended was not to talk at all until you speak to a lawyer..... Hope this helps some of your guys.
And all who have had a controlled delivery speak up!