Reed-Solomon? Really?

Red Book audio CDs use CIRC, cross-indexed Reed-Solomon codes. 'Tis true.

If that were the case, then any errors should be correctable by the drive, not just reportable.

Not any errors, of course, just most small errors. C2 error reporting tells the ripper which samples even Reed-Solomon couldn't correct. In this case the drive usually interpolates the missing values, in the hope of not causing an audio click.

Peter