Hi, should there be a desired value set on maximum liability?
Well, it shouldn't per se, but it would be helpful if you want to prevent a huge bet to be placed in your account.
Connieanne, have you been in contact with BetFair regarding the hack? If unsolicited bets were made from your account, they should be able to tell you when and by which means (i.e. the web site or bot) they were placed. In MF Pro all users are working through a software ID appointed to us by BetFair, so it should be visible whether those bets were placed through MF Pro or not.
Also, like Time suggested, do check your logs to see if those bets are mentioned there, and - what is more important - which procedure initiated them.