2011-01-07: Chat "whitelists" no longer allow specified users to talk regardless of their rep. Users with less than 20 rep now get only four hours of chat time before being locked out.
The linked posts also has this comment by Jeff Atwood:
we are closing this loophole. I support a one time 4 hour access link, but not this forever and ever backdoor.
I thought that write access to a room for a user who is below 20 reputation points can only be granted by a moderator or some other diamond-bearing user. (This is mentioned in several posts here on meta. And I have also seen some occasions when this was done by moderators on request.)
I gather that long time ago, granting access to low-rep users was possible to any room owner, not only mods - but this was changed in 2011. What surprised me was the mention of this access for four hours - I haven't heard about this before and I did not find some documentation of this anywhere.
It's very likely that this no longer exists. (After all, I only found this mentioned in an announcement from 2011.) But still, I have to ask - both out of curiosity and because I can imagine that on some occasions it might be useful.
Question. The above quotes mention short-time access for low-rep users. Does this feature still exist? Is it documented somewhere how exactly it works?