Won't work, whoever is with you will stop it
Is this a 100% certainty is it?
In my opinion this is a just a malicious way to fuck with people, why else would you go through all this trouble when there are plenty full of methods that require similar or less courage to succeed. But if that's your goal sure I guess you really showed the pilot.
If it's a way that works then that's the reason. You're acting as if anyone wanting to do it this way is looking to hurt people.
That's not the case necessarily, sometimes it's just a case of finding a method that works.
If I don't have euthanasia/maid, if I don't have guns, no easy access to things like SN and the necessary drugs along side it, then my options are limited down to hanging, drowning, jumping and train.
Drowning is just a terrible way to die, hanging is hard to get right and painful, train is risky.
Falling from a very high height is is a good way to ensure success and that's why some people do it, and if you don't have easy access to high cliffs, then falling from a high building may be necessary.
A hot air balloon may take you up to a very high height from which CTB is very close to certain.
That's why people consider it, not because they are sadistic but because it may be literally one of the few options they have available.
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Example - I posted threads previously on using the train method and had a guy telling me that I should never use this method and he'd never consider it in any circumstances.
He went to go CTB via jumping from a bridge, but the bridge was monitored heavily and had a suicide barrier which he was not aware of while planning his CTB.
On the day of his CTB, he was so sure he wanted to die, that he killed himself by, you guessed it, by train method. The exact method he preached to everyone about and how it was awful and selfish, he did it to end his suffering.
If you were suffering enough you'd want a way out, and morals would go out the window. Trust me.