They did. I posted the actual press release for it. The physical address is not announced.
He was, and was publicized. His name is Andrew Witty. Did you just get here?
I saw the announcement you linked to. It also contained a link to the investor relations page for details. Not sure what details were in the link earlier as it now goes to a statement about the killing. But it wouldn't surprise me if the location (conference hotel) was available there. While not widely advertised, they probably didn't regard it as secret. The announcement
did state the date and the start time for the conference. (8 AM)
It's also possible that someone posted the location on their LinkedIn. I see that type of thing frequently: "Attending ______ Conference at ______ hotel in _____ next week!" or "See my presentation streaming live from _____ on Monday!" People post ◊◊◊◊ on social media all the time. My brother-in-law posts pictures of the socks he wears most days. (No, I don't know why.) And sometimes pictures of the food he eats at a restaurant. (Why????)
Putting aside the assumption that this particular person was the
specific target, I think that's all the necessary information needed. That is, other than being able to identify several high ranking executives that would likely be there. Might not even expect them to be staying at a different hotel.
So if he knows the conference hotel, and that the event starts at 8 AM, he has what he needs. He can guestimate the times that one (or more) of his potential targets might step outside. Likely times: Before the start (7-8 AM) Around lunch (12-1) towards the end of the day (4-6) and likely "break" times (around 10 AM and 3 PM) These are times attendees are likely to be outside, coming or going for meals, conversations, or just fresh air. His plan may have been to be around during these times. It just so happens that he saw a target early in the first opportunity window.
(This is all based on agendas and behavior at conferences I've attended.)
The only reason detailed information is needed is if there was a single specific target, which may or may not have been the case.
The phone call could have been related. Or it could have been just talking to some friend about something unrelated. Or it could have been AT&T calling to sell him a fiber-optic plan. (They call me several times per day.)
Speculation can be entertaining, but there's not enough information to rule out many scenarios at this point.