Does locking announcements keep students from seeing them?

All my announcements from last quarter were carried over, which is great, but I don't want to go through 30-odd announcements and delay publication. Does locking keep them from student eyes? And if not, what purpose does the lock tab serve?

It would seem to be a flaw in Canvas to not have an easy way to block the carried over announcements. I'm sure a tweak could easily be established.