"Steven P. McNicoll" wrote in message news:lIRjc.5945

VFR aircraft are separated from IFR and other VFR aircraft in a TRSA, but
participation is voluntary. VFR aircraft are separated only from IFR
aircraft in Class C airspace, but participation is mandatory. All aircraft
are sequenced to the primary airport in Class C airspace, not so in a TRSA.

One thing that VFR's should note, that while participation is voluntary in the TRSA,
many TRSA towers get a bit testy if you don't go in through the TRSA-approach
control.