If setting out sailing etc., three regions, in particular, absolutely warrant a look into advisories etc.: the waters around Malaysia / south of China / etc., off the east / west coasts of Africa (more recently, west, but sometimes east), and certain areas of the Caribbean.
The ocean is much like other regions with human traffic in the sense of there being "bad areas" ... but, it's also different in ways that kill people all the time. It's not worse than land, per se, but, definitely easy to get into trouble without at least a little education (generally, best to get from reputable people / services that exist in particular regions - of course, you can still get into trouble, but, much less so than people who just hop on vessels with no real experience for "an exciting adventure" ... too easy for it to get way more exciting than almost anyone raised on "Hollywood" movies wants in real life).
Note that piracy - robbery by boat - is associated with lawless regions. It will be hard for some people to accept that the Bay Area has declined so far.
I was raised and worked as an adult in San Francisco. It has always had two faces: the truly friendly, groovy, nice side; and the truly dangerous, menacing, lawless side. There are people who firmly, even angrily, deny that San Francisco is any more dangerous than any major urban center, not to mention actually lawless. For them, perhaps it is not. But these are the same people who will deny that this kind of thing - robbery by boat - is piracy. Because to them, and this is my point, piracy only happens in lawless places (or the quaint past) and San Francisco is not lawless QED.
https://knowyourmeme.com/memes/look-at-me-im-the-captain-now
From a 2013 "big budget" movie (Tom Hanks etc.) about a piracy incident during a period when the Somali coast was notoriously dangerous:
https://en.wikipedia.org/wiki/Maersk_Alabama_hijacking
If setting out sailing etc., three regions, in particular, absolutely warrant a look into advisories etc.: the waters around Malaysia / south of China / etc., off the east / west coasts of Africa (more recently, west, but sometimes east), and certain areas of the Caribbean.
The ocean is much like other regions with human traffic in the sense of there being "bad areas" ... but, it's also different in ways that kill people all the time. It's not worse than land, per se, but, definitely easy to get into trouble without at least a little education (generally, best to get from reputable people / services that exist in particular regions - of course, you can still get into trouble, but, much less so than people who just hop on vessels with no real experience for "an exciting adventure" ... too easy for it to get way more exciting than almost anyone raised on "Hollywood" movies wants in real life).