iCal feed contains HTML in the Description property

I know, I did it on purpose. All clients that I have tested where able to display it.

One client, Apple's iCal, shows all the markup. Do we need to specify an altrepparam of text/html or something? Here's the spec:

4.8.1.5 Description

   Property Name: DESCRIPTION

   Purpose: This property provides a more complete description of the
   calendar component, than that provided by the "SUMMARY" property.

   Value Type: TEXT

   Property Parameters: Non-standard, alternate text representation and
   language property parameters can be specified on this property.

   Conformance: The property can be specified in the "VEVENT", "VTODO",
   "VJOURNAL" or "VALARM" calendar components. The property can be
   specified multiple times only within a "VJOURNAL" calendar component.

   Description: This property is used in the "VEVENT" and "VTODO" to
   capture lengthy textual decriptions associated with the activity.

   This property is used in the "VJOURNAL" calendar component to capture
   one more textual journal entries.

   This property is used in the "VALARM" calendar component to capture
   the display text for a DISPLAY category of alarm, to capture the body
   text for an EMAIL category of alarm and to capture the argument
   string for a PROCEDURE category of alarm.

   Format Definition: The property is defined by the following notation:

     description = "DESCRIPTION" descparam ":" text CRLF

     descparam = *(

                ; the following are optional,
                ; but MUST NOT occur more than once

                (";" altrepparam) / (";" languageparam) /

                ; the following is optional,
                ; and MAY occur more than once

                (";" xparam)

                )

http://tools.ietf.org/html/rfc2445#page-81