Effects of mount -rw -o remount / as user root?

Question

ubuntu

If you write this command from the root user (not rescue mode):
mount -rw -o remount /
Then it will have no effect, since, by default, "/" is already in the "read / write" state, right?
This command is for enabling the rescue/livecd?

Answer 1

will be if you have a riadonly root partition or something else strange