As documented in the manual, the -r option clears write permission
« because the filesystem will be mounted read-only in any case. »

The problem comes when copying a file from a CD: cp will preserve the
permissions of the file, and thus, after the copy, one has to chmod +w
it before working with it, which is a pain.

Shouldn't the default permissions have u+w so as to avoid the chmod ?
(when the original file has u+w permission, for instance).

Samuel