The reason for this theory is that if you use a fake name, you can write "not at this address" on the package and leave it by the door unopened (but still inside your house) for a day or two in case the feds come knocking. If they are going to come, it will likely be the same day that the package is delivered. Then if they do show up, you can say "see, I was going to drop it back by the post office" and they would have a very difficult time proving you had any knowledge of its contents.