I don't know how many people actually make use of Map's Security Admin but it seems there aren't many. Some basic information about Security Admin can be found here. We have seen a couple of issues I want to document here for reference:
(a) some functionality is broken when using a Guest
We found out that some features in Map are broken when using a guest instead of the main data document (such as soft split/hard split not working properly anmyore, wrong form opens up for selected feature). Fortunately Autodesk has fixed that (for Map 2013 in form of hot-fixes).
(b) performance issue when creating a guest
That seems to be depending on the Oracle version in use. There is a workaorund (see here). Unfortunately the SQL profile suddenly stopped haveing any effect in our database and the re-creation of a new profile has not yet solved the issue. But hey, it worked very well for almost 2 months. Some discussion is going on here.
(c) tables of wrong schema are displayed
When you open your guest user in Security Admin you might be surprised to see a completely wrong set of tables. In fact Security Admin shows the tables and views of different Oracle schema - not the one you have created the guest role for.
This will happen if your base schema (main document) contains synonyms. Security Admin displays the tables/views of the schema where the synonyms are pointing to. The only way to work around this - as far as we know - is to create PUBLIC synonyms instead of "normal" private ones.
Map 2013, SP2 (and a few hot-fixes)