It's pretty easy to scrape your own calendar events in Meta. I'm not sure about others' as I'm not a manager, but I wouldn't be surprised if it were visible as long as someone is in your report chain.
It's been a while so I don't remember the specifics, but the I think the request came from someone working at Accenture from one of the FinTech teams? At the time the proposal had both technical limitations and performance implications on top of the privacy issues. To do it right would have meant standing up a new set of client exchange endpoints and permissions that were far too permissive so the task just got ignored for a long time and I think that manager behind it went away eventually or they settled for public data inside the company.
The only report chain based permissions were around distribution lists which were just some powershell scripts that walked AD every night. These also got used for security groups to gate access to some things. Be default, calendars were visible to all authenticated users unless you made them private or individual events private. The meeting tool leveraged this for example.
I was working on corp email (among other things) there from 2009 to 2016, so I can't speak for now.
The only report chain based permissions were around distribution lists which were just some powershell scripts that walked AD every night. These also got used for security groups to gate access to some things. Be default, calendars were visible to all authenticated users unless you made them private or individual events private. The meeting tool leveraged this for example.
I was working on corp email (among other things) there from 2009 to 2016, so I can't speak for now.