mount changes permissions of directory?

[Joerg Johannes <liste_joerg@gmx.de>]

Hi List

Why does a mount change the file permissions of a directory?
Example:

ls -l /mnt
drwxr-xr-x    2 root     root         4096 2003-01-20 18:29 d
mount /mnt/d
ls -l /mnt
dr-x------    1 root     root         4096 2003-01-24 09:22 d

?????
/etc/fstab says:
/dev/hda7       /mnt/d          ntfs    user,noauto,ro          0       0

Any idea?
joerg