Why don’t calendars do time zones?

My laptop and my palm both understand Time Zones. I understand Time Zones. Why don’t my calendar applications (Oracle’s Calendar and the Palm Calendar in the handheld) understand Time Zones. What I want:

(1) When I create an appointment I should be able to mark the Time Zone for the appointment. I should also be able to make appointments that are Time Zone neutral – not tied to a Time Zone.
(2) My clients (Palm and Desktop and Web) should all understand Time Zones and should be able to shift the alarms to compensate for my changes in Time Zone.

How would I use this? Well…

– If I get an invite to join a conference call at 11AM EST, I could just enter that time without adjusting for my local time zone. Same with UTC time.
– If I changed time zones (say fly from Madison to San Francisco), my alarms would change to be appropriate. As it is now, if I fly to California, I need to keep track of the fact that the 10AM meeting is really a 10AM Central time so I need to set an alarm 2 hours earlier.
– But I can’t do a global change because some things might be dinners in California so they need to stay on Pacific time.

We have these bright machines that understand our location and time zones. This is the perfect task to offload to these systems. It is simple and fussy and requires sifting through events and applying rules. Perfect work for a computer.