DGF, I am a pro massage therapist as well, so perhaps my opinion would interest you...
If your friend is a pro of any experience, then she has probably dealt with hyperticklish clients before, and can probably minimize the problem (particulalry if forewarned)if not eliminate it entirely during your session. What usually works best for me is to slow the strokes down considerably, and use more depth of pressure....
As far as your family finding out, that also shold not be a problem. Part of professional ethics for therapists is confidentiality: she should not be talking about you, your session, your body, or your ticklishness with anyone at all, especially not anyone who knows you. Even when 'talking shop' with other therapists, it is most appropriate to use anonymous references: e.g. "I had a client the other day who was very ticklish on his feet... how do you usually deal with that" or "I have a client who has pain in his left triceps... do you know any good triceps stretches?"
So, on the professional level, there should be no problem. On the personal level... do you want her to tickle you? Are you excited by the thought that it might happen? If so, then perhaps you should talk with her before the session so she undertands this aspect of you. Sometimes the line between professional touch and personal touch can become blurred during a session: sometimes this is OK (when both client and therapist feel the same way) but often miscommunication and misunderstanding can lead to awkwardness and embarrassment for both parties.
Just a few thoughts, from someone who knows.