Family - - - too little, too late

I've noticed that it's nearly impossible to get anyone to commit to anything more than 20 minutes in advance these days. And that they don't take kindly to being out of luck for not accepting in timely fashion. And no, they don't learn from the experience, either. Only thing you can do is issue the invitation, and shrug it off if they come back to accept too late. Whatever you do, don't pester them for an answer. All you'll get is frustrated. Ask, when the drop-dead date for reservations passes, make other plans. When they show up on your doorstep expecting to go, sorry, it's too late, we made other plans when you declined-by-ommission by the date we had to act. You snooze, you lose, that's the way the world works.