https://www.deadmansswitch.net/
There was an episode of one of those crime shows that revolved around a site like this. Except it was the rapture not individuals dying. Iirc if the owner of the page didn't check in for 24 hrs it sent all the emails. He got murdered all the emails got sent out and one of them was a murder confession. Weird episode, I wish I could remember which show it was. Feels like a CSI episode
**Did some googling. Law and Order - 'Rapture'
That episode is probably the main reason I could never trust an anonymous entity not to send an email telling my loved ones I'm dead prematurely.
As I mentioned in another comment I was thinking about this sort of site the other day and this is the other major issue that occurred to me. Not to mention that if they can send it, they can read it - or you have to encrypt yourself and prepare your recipients.
I was just thinking about this the other day. The trouble is longevity. Even with the pricing this site uses I have doubts about the longevity. What if the owner dies and the site goes out of service?
I'd only count on this for the span of 5ish years, not 30.