unfortunately the best answer i can give you is that it depends, even city to city protocols aren't set in stone/properly followed most of the time. i've had friends who'd picked up by the state police and not even reported to family of their departure (let alone note), whereas i've also had friends who's entire apartments were boxed up/family notified/etc., mostly due to the nature of the method, the emergency contacts listed on medical case files at coroners office, and honestly, how much effort the cop pig felt like doing that day.
if you're trying to get something to a particular person and ensure it's arrival, your best bets are either scheduling an outgoing email/text for a future date, or using the postal system (with physical note left nearby if you're really worried about it arriving)
(also, southwest USA here, because it can vary by location too)