Question - if I am promoting a webinar where the ICS file says 10 am PST, but the webinar crosses over to Daylight Savings, and is 10 am PDT, should I say in the ICS file that it is 9 am PST? when it is on someones' calendar it comes up at 10 am PDT on March 21? Thoughts?
The ICS file delivers the date as a UTC timestamp. It's up to the client to readjust the time based on local timezone + daylight saving offset. The file itself does not contain timezone information.
(In sum: No, you definitely should not be making daylight saving adjustments yourself.)