I was going to be #6 (I think) with 'no'. I would hate it.
I love the anticipation as much as the event itself, and onetime someone wasn't coming home for Christmas, I spent the entire month crying at every mention of Christmas (I'll Be Home for Christmas was the worst song ever.) At that time, I had no one else to think about, like my other children and grandchildren, so that would have made a difference. If I had thought there was over a 50/50 chance he'd be there, I would want to know.
As soon as he gets on the plane, I would want to know especially.
The surprise is a surprise at anytime. We were just as surpised that we were getting twin granddaughters early on as we would have been showing up at the hospital. We were just a surprised that we were getting 25th and 40th anniversary parties in the planning stages as we would have been showing up for dinner somewhere.