What do most people believe about death when they've left the faith? Do they cling to the soul sleeping doctrine or just not believe in anything?
My grandmother was terrified when my JW aunt sent her some literature on death. It was supposed to make her feel better, but going down into the cold, dark grave just feet from her dead husband really spooked her. The JW doctrine just doesn't wash considering the information that's been gleaned from extra-biblical sources discovered in Egypt in 1947-48. As non-canonical books were banned in the north, the Coptics buried up their scriptures so they would not be destroyed. In this library, no one seemed to believe the soul sleeping doctrine. In fact, you really have to warp the canonical NT scriptures to get it to work. The apostles, in fact, viewed the body like a garment for the spirit that could be put off at death. Paul, in speaking of a man who visited the third heaven, said whether this man was "in the body or out of the body," he could not tell, he said. Also, based on some credible after-death experiences people have had (and conceding there are some non-credible accounts out there), I just don't see the argument for soul sleeping.
The thing about a corpse is that it looks empty -- like a shell. It doesn't just look unanimated, it doesn't even look like real in most cases. People who have discovered crime scenes often say of the body, "I thought it was a mannequin." If the body is just a shell, it doesn't take adventists and atheists too long after death to realize they were wrong. On the other hand, if the person ceases to exist, no one will know.