We have a 'family friend' who is rather passive aggressive and snipey, but see them rarely. I invited them over for today several weeks ago and they said 'yes that sounds fine but will email to confirm'. They didn't email and I didn't chase as a) the ball had been left in their court and b) I really wasn't bothered if they didn't come anyway as they can be quite rude but I keep contact and remain pleasant for the benefit of other family members, and my children love them anyway. So this morning a good friend called and asked to do something together today. I said yes, but am now panicking the original guest will just turn up in the meantime. Have I behaved badly? If they do just turn up, would it be bad form to act completely surprised and just say 'I assumed you were not coming as you never emailed to confirm as agreed?' Now I have typed it, it all seems rather silly.