I personally don't really think that a person, who is making that a leap and decide and stop existing, has a 'clear' mind. It may be an objectively rational decision ( and frankly, I believe it is up to each of us to make that decision ), but I would be hard-pressed to argue that 'this individual, who I find of sound mind opted for the chair'. There is a reason society has certain level of concern for those that try and fail.
It is possible that I do not have enough of a population sample, but I personally see it as part of an effort way to keep world population control at certain level. Before anyone accuses me of tin-foiling, I mean it in the same sense as that there are efforts to prevent suicides by means of suicide prevention hotlines.
I guess what I am saying, as a society, we are grappling with with two competing interests:
1. We care about certain individuals and we don't want them gone from our life. 2. We care about certain individuals and we want them to have control over their own body.