FORM #1: DATE WITH LOCAL TIME
The date with local time form is simply a DATE-TIME value that
does not contain the UTC designator nor does it reference a time
zone. For example, the following represents January 18, 1998, at
DATE-TIME values of this type are said to be "floating" and are
not bound to any time zone in particular. They are used to
represent the same hour, minute, and second value regardless of
which time zone is currently being observed. For example, an
event can be defined that indicates that an individual will be
busy from 11:00 AM to 1:00 PM every day, no matter which time zone
the person is in. In these cases, a local time can be specified.
The recipient of an iCalendar object with a property value
consisting of a local time, without any relative time zone
information, SHOULD interpret the value as being fixed to whatever
time zone the "ATTENDEE" is in at any given moment. This means
that two "Attendees", in different time zones, receiving the same
event definition as a floating time, may be participating in the
event at different actual times. Floating time SHOULD only be
used where that is the reasonable behavior.
In most cases, a fixed time is desired. To properly communicate a
fixed time in a property value, either UTC time or local time with
time zone reference MUST be specified.
The use of local time in a DATE-TIME value without the "TZID"
property parameter is to be interpreted as floating time,
regardless of the existence of "VTIMEZONE" calendar components in
the iCalendar object.