Right now, when copying files, the permissions of the source are also applied to the destination file. If the source is on readonly media, the destination should be writable to the user nevertheless (chmod u+rw).
Committed with revision 20275. 2006-03-07 Benedikt Meurer <benny@xfce.org> * thunar-vfs/thunar-vfs-xfer.c: Automatically give write permissions to regular files and folders copied from read-only media. Bug #1555.