Jon Udell explores the issues.
As Udell says, "When a computer in one timezone schedules an event in another timezone, the computer doing the scheduling needs to be able to accept and display both. Since the feature usually isn't needed, it should ideally be hidden but easily accessible. That's admittedly a thorny user interface problem. I'm sure programmers could solve it -- if they weren't so indignant about humanity's perversion of astronomical time. And now, if you'll excuse me, I've got to go. It's 0100 UTC and the sun's coming up."