When I click on the message saying a post is locked, the 50 reputation required pop-up comes up as if it wasn't locked:
This would probably confuse new users as it is basically contradicting the locked post message.
I have found another locked question on Ask Different (What was the very first Apple product?) but the reputation thing does not pop-up when I have 50+ reputation there, so we can rule out the possibility of it just not checking for anything (ex. over 50 reputation) so it displays all the time.