Dual-Class Fool?

After I wrote up yesterday's Fool class, I started thinking about class-switching for the Fool or for the related class, the Tourist. First, switching to one of those classes after character creation is strictly forbidden without magical assistance of some kind. Fools and Tourists, and maybe some other hypothetical classes, are practically examples of "race as class" as people normally use that term, even if people don't normally think of a fool as arace. You have to be born a Fool, or you have to grow up in a foreign land to be a Tourist. Maybe they should be called "cultures" rather than classes. You can only have one culture, and it replaces your starting class; whether or not it replaces your race depends on the setting. (Hmmm, now I'm feeling the need for Elf Tourists...)

The key factor to look for is whether the class has a limitation that doesn't apply to other characters in general: the Tourist's inability to speak local languages, including Common, or the Fool's inability to detect lies or disbelieve illusions. The lack of a common ability is a clear signal that "this class is different". Both classes use an inverted prime ability score, Wisdom in both cases, which might be a good rule to follow for future classes like these.

Can a Fool learn to be something other than a Fool, or a Tourist learn to be something other than a Tourist? I'd say there's the normal possibility (score 16+ in prime ability of new class,) but the limitations of the original class must always spply. So, if you start as a Fool and change to some class that reduces surprise for that character, the Fool doesn't get that benefit.