PliotronX,
Never underestimate the power of Adaptec / ROXIO software -- in other words, DirectCD. I've seen some CD-RWs that were definitely "coasters". Couldn't erase them, couldn't run the ROXIO Scandisk utility on them, couldn't format them. I've never seen a CD-RW coaster that had just been written to as thought it were a CD-R. I think you have to format it UDF and then have a problem while writing to it to produce the coaster phenomenon on a CD-RW.
Regards,
Jim