Planning a party for DD. Its at a busy time of year so have given 6 weeks notice. It's an activity and we can only invite 10 kids. We have a list of potential invitees to work down if any of the first choice 10 can't make it. We've had 9 yes responses and 1 'can I let you know nearer the time?'
Either you have something in your diary or you don't. You're either prepared to put it in and forego anything else that comes up or you're not. Surely you should say yes or no and not 'I'll wait and see if there's something else I'd rather do'.
I don't really want to be inviting someone else last minute if she can't make it.