Sean,
My airbnb can be canceled up to 3 September. As long as Tony is attending, he could still use it even if I am unable to attend. I can wait a similar amount of time to decide on canceling my flight for credit.
I continue to plan to attend unless my prospects for getting into the UK and back home are too dodgy.
Not worried about my prepayment. If I have to cancel last minute, then the funds can either go to the clubs or buy a round of drinks.