![/!\](/moin_static19/modernized/img/alert.png "/!\"){kind=small}
Note: this page is obviously not about disabled accounts (u.disabled is True), but about users not having an account yet.
Help guide users when a wiki and/or account creation has been disabled
One of the signs of good software is that it helps guide its users to a solution when a problem is encountered. For a wiki, if the wiki manager(s) has disabled the ability for anonymous/new potential contributors to make changes to the wiki, and require an administrator to add such contributors to a privileged group, you need to inform the new contributor of that requirement and how to go about contacting the administrator(s).
This should be done at account creation time. Also, instead of having a grayed out, inactive label marking wiki pages as 'Immutable Page' make the label an active button that puts up a pop-up with tells the user who to contact in order to be added to the privileged list. As it currently exists, a user is left without a clue as to how he/she could make a contribution and that can be frustrating especially when they have encountered something that is wrong and in need of being corrected.
This sort of feature should be an inherit part of your wiki software, and not left as an option for administrators to add as a piece of documentation on their wiki.
Well, I obviously have a different opinion (until someone convinces me otherwise). 
Moin usually lets everybody create an account.
If a wiki admin chooses to handle this more restrictively, it is also his task to inform users about the procedures and requirements for creating accounts and/or editing pages (these can be very different, so there can't be generic support for that in the software).
Usually, the wiki admin should gives contact information (or other help about account creation / editing permissions) on the front page of the wiki (or a page linked from there).
Stuff on which procedure might depend:
- some company / organisation policy (who may have an account, who may get into some groups, who may edit some specific pages...)
authentication method(s) (these can be external to moin, e.g. LDAP/AD, GivenAuth, ...)
- ACL configuration
- group configuration
Also, your assumption that there can be some sort of solution for everybody and that moin is technically able to tell that is wrong.
You can have individual permissions on each page. The permissions on some pages might be that practically nobody (or only admins, or only specific group(s) members) is allowed to modify them.
As long as you are not logged in, moin does not know who you are, does not know in which groups you might be.
Even if you are logged in, moin does not know into which groups you might be allowed to get added by some admin.
Thus, trying to offer some generic "help" there might be impossible or misleading.
-- ThomasWaldmann 2014-05-04 12:39:36