"find" problem

[Dean S. Messing]

In doing more experimenting with find, I discovered that
/ is evidently fstype "rootfs", whatever that is.

Looking in /etc/mtab I see:

   rootfs / rootfs rw 0 0

and 

   /dev/mapper/vg00-lv_root / ext4
   rw,relatime,user_xattr,acl,barrier=1,stripe=32,data=ordered 0 0

In fact,

   find /  -fstype rootfs -print

prints all the files and ordinary directories under /.
None of the ext4 mounts are entered, nor are /proc or /sys, &c.

   find /  -fstype ext4 -print

only prints the entries in ext4 directories mounted in /.

This behaviour thoroughly breaks some of my scripts.