Apparently this is still a problem for at least some percentage of non-old-timers. The Discourse defaults still have this conflict in iconography:
Closed Topic: You don’t have access and can’t post here.- Available Category: You do have (special) access and can post here.
… and I’ve had a few reports recently about people confused by the two separate meanings for the same glyph.
Is there any easy way to bulk-change these icons (for revealed categories) to the unlocked icon?