The idea is a bit tricky.
What happens when people time out in an "open" clan, they close, they log in =/
Usually in areas that are not in an event but are reachable to you, it matters little.
I'd rather go with a scrying idea than a real visit. Which is, I realize, not very roleplay-ish.
On what can you agree on that makes sense?
Participating in the chat like scrying? Actually being in the clan hall (seeing most options + clan description)?
It will be a lot of work, because it'd need an invitation system added which also can revoke access prematurely. That's a lot of test cases.