availability question

What's the interaction of (v)availability with date-ranged queries?

Do we need a limit-availability-set? (probably overkill)

Does finding any (sub)component in a supplied date-range imply returning 
ALL of the available components?

In:

         BEGIN:VAVAILABILITY
         ORGANIZER:mailto:bernard <at> example.com
         UID:20061005T133225Z-00001 <at> example.com
         DTSTAMP:20061005T133225Z
         DTSTART;TZID=America/Montreal:20061002T000000
         BEGIN:AVAILABLE
         UID:20061005T133225Z-00001-A <at> example.com
         SUMMARY:Monday to Friday from 9:00 to 17:00
         DTSTART;TZID=America/Montreal:20061002T090000
         DTEND;TZID=America/Montreal:20061002T170000
         RRULE:FREQ=WEEKLY;BYDAY=MO,TU,WE,TH,FR
         END:AVAILABLE
         END:VAVAILABILITY

If we search for a date range that covers the weekend only the AVAILABLE 
doesn't cover it but the date range on the VAVAILABILITY does - though 
what does the DTSTART by itself mean?

For events

For cases where a "VEVENT" calendar component