I only enter locations in events for places that aren't where I'm already going to be. If I'm in the NY office, I don't bother to put NY in my reminders/events

I only enter locations in events for places that aren't where I'm already going to be. If I'm in the NY office, I don't bother to put NY in my reminders/events. Moreover, meetings across offices may have rooms booked in many locations; how do you know which is for whom? If I want to book a meeting for next week, and I'll be in NY, but I'm in SF now and someone from SF is dialing in, how does it know which time zone to use?