Actually, the comment is old. Look at the removed line 91-92:
checked  = upcrP->check(RegisterContext, XML, "", "", 0); // Cannot use UpdateContext here ...

Seems to mean that the requestType should have been UpdateContext but RegisterContext is used instead to avoid a problem in the unit test.
In UpdateActionType.cpp there is no 'if (requestType == UpdateContext)' so the comment is OLD.
I will simply remove this comment.