Comment # 1 on bug 1157773 from Neil Rickert

It is not as simple as it looks.

# id
uid=0(root) gid=0(root) groups=0(root),65534(nobody)

Yes, it looks as if I am root.  But:
root@nwr2 # ls /root
ls: cannot open directory '/root': Permission denied
root@nwr2 # less /etc/shadow
/etc/shadow: Permission denied

Another test:

root@nwr2 # ls /tmp/foo
ls: cannot access '/tmp/foo': No such file or directory
root@nwr2 # touch /tmp/foo
root@nwr2 # ls -l /tmp/foo
-rw-rw-r-- 1 root root 0 Nov 26 09:58 /tmp/foo

But, if I examine that file from another terminal:

23% ls -l /tmp/foo
-rw-rw-r-- 1 rickert rickert 0 Nov 26 09:58 /tmp/foo

It looks as if "unshare -r -n bash" makes me a fake root.