Earlier quoted context omitted.
Do you have any suggestions of a limiting principle, then, or do you just think suicide should never be an available service others can offer and must always be done by oneself?
I'm honestly not sure. I recognize the complexity of the issue, and for what it's worth I used to be totally in favour of legalizing euthanasia until I saw what it looks like in practice in countries that have done it. But my current feeling is that the limiting principle should be we don't do anything in any way to normalise suicide, to tell anyone that suicide is a reasonable solution to their problems, or to give…
The edge-case is that the person wants to become an early suspended customer of a cryonics organization. Already there have been successful suicides from people who stated they would have preferred to be suspended and have the very small chance of actually getting a second chance at some distant point in the future, but there are various legal obstacles as well as practical ones to that, and so these people are just as assuredly gone forever as anyone else.
Besides being complex, it's also an old issue. You might enjoy reading this case report from 1993 about a suicidal person who wanted to be cryopreserved: https://www.cryonicsarchive.org/library/complete-list-of-alc... He did eventually shoot himself, and unlike others there was at least a brain preservation in the end, but it's pretty far from an ideal one (and no one knows if even ideal preservation is good enough for future reanimation/emulation; I'd bet against it but obviously wouldn't rule it out). More recently, in late 2018 the first person was cryopreserved while using California's new end of life option act to hasten an otherwise painful demise from stage 4 cancer. (Short version: https://www.cryonicsarchive.org/library/complete-list-of-alc... Long version: https://www.cryonicsarchive.org/docs/alcor-case-report-a-199...)