Re: a question on VJOURNAL in RFC2445

In RCF2445 under "4.6.3 Journal Component" it states:


 >Description: A "VJOURNAL" calendar component is a grouping of
 >   component properties that represent one or more descriptive text
 >   notes associated with a particular calendar date. The "DTSTART"
 >   property is used to specify the calendar date that the journal entry
 >   is associated with

Yet, DTSTART is not a _required_ property of a VJOURNAL entry. This seems 
to me to be an error in RFC2445 - can someone give me a use case or other 
reason for an undated VJOURNAL entry?

Thanks
Tim Hare
Interested Bystander, Non-Inc.