My idea is it that it is a "bad thing" to code into the name of the subroutine the fact whether or not the subroutine should be externally "advertised".

Far better, IMHO, would it be to put this attribute into the dispatch-table like so:

%query=('action1'=>[\&handler1,'public'],
       'action2'=>[\&handler2, 'public'],
       'action3'=>[\&_do_not_advertise_this_function_externally,'priva
+te'],
       # and so on
);
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Now you will have to dereference one level deeper to get the sub-reference and the attribute, but that seems a small loss given that you now have the attribute handy in the dispatch-table.

If ever you want to change the public/private atribute, all you have to do is change this atribute in the dispatch-table. In your system, you would have to change the dispatch table and the actual subroutine name itself (and if you ever call such a subroutine directly from somewhere else in your code, you will have broken your program, unless you change the subroutine-call as well -- messy, messy).

With the "attribute" solution you can even change the public/private programatically if necessary. [Whole new vistas of enormous possibilities unfold before your inner eye]