Hi smatticus,
I know when I had the presentation before the interview they were slightly unsure (i.e. they weren't sure whether the wording in the presentation was the BA Open Day, a special FPP Open Day or the FTO Open Day!). Classic BA really....someone not being specific and the information then gets passed from person to person with no one really sure what it means!
I'm an internal applicant and asked Lindsay Craig as soon as I'd found out I'd been accepted onto the scheme. He clarified and said it meant that it was an FPP-specific family day that would be held just before your course starts. Your family will have the chance to come down to Cranebank/Engineering and play on one of the sims as well as have the opportunity to chat with the recruitment team and fellow coursemates etc etc.
There will of course be an FTO-specific open day for you and your family too.
Luckily I managed to get tickets for the 7th June through the staff ballot!