Timecave reported me to local law enforcement even after I had cancelled the email I had intended be sent upon my death. Describing that situation was the reason I made my very first post here. You can use the search function to find the fairly long discussion.
Boomerang is Google, and Google scans all emails. There's a chance you could be reported to local LE.
My current plan, should I again attempt to ctb, is LetterMeLater: basic scheduled email. There's also Dead Man's Switch, if you want to go the route of needing to check in, and if you don't check in (because you're dead) the email gets sent.
This subject has been covered in considerable detail in the last four months. You might want to do a search, since I can't remember all the details.