Dead Man Switch

This week I read a post about the death of the Boeing whistleblower, and how Boeing might have suicided him.

I don't care about if the rumors are true or not, however someone mentioned in the comments that in such situations one should always have a Dead Man Switch.

For those who don't know a Dead Man Switch is basically an action TBD in case you die, like leaking documents, send messages/emails, kill a server etc . . .

The concept tickled me a bit, and I decided I want to build a similar system for myself. No, I am not in danger but I would like to send last goodbyes to friends and family. I think it would be cool concept.

How would you go and build such service?

I thinking of using a VPS to do the actions because it would be running for a while before my debit card gets cancelled.

The thing that is bugging me out is the trigger, I will not put that responsibility onto someone that's cheating, so it would have to be something which can reliably tell I am dead and has to run regularly.

Where is what I come up with :

• Ask a country association through email if am I am dead.

• Check if I haven't logged out on my password manager in a week. If it's even possible.

TLDR; Give me ideas on how to build a DEAD MAN SWITCH and what triggers should I use.