Most of the time when I hear about people who have gone ahead with it, its been people that have told nobody at all...family, friends or anyone how there feeling. They write a letter, sort out loose ends, and often plan it well in advance....thats why when you see a GP and you tell them your depressed, they ask you:
a) Do you feel suicidal
b) Have you been planning it..and if so, how developed are your plans.
The more developed they are..the more alarmed the doctor gets, and the more likely you are to find yourself in hospital.
I imagine there would be a few people every year that post on the forum and go ahead with it. Its a terrible, terrible thing...and for what its worth I believe those people that get on here as a friend or family member to let us know somebody has gone ahead with it...I cant imagine doing that as some sort of windup.