Since your emergencies have past...
I used a smack pack (Wyeast) a few days after smacking... I didn't want to make a starter wort because that's the whole beauty of the smack pack to me.
The first time I did it, I did so because the yeast was delivered the coldest week of the year and it was a bit frozen... so I defrosted it in the fridge (nice and slow over a couple of days) and I wanted to make sure it was still viable after the ordeal. - It clearly says "don't freeze" -
Anyway, I smacked it a few days before I was going to brew to give myself enough time to get some more yeast if I needed it so I would have to postpone brew day. It turned out to be just fine.
Just this weekend, I smacked a pack on Friday night for a brew on Saturday, but I wasn't able to brew Saturday... I ended up brewing Sunday afternoon. It's working pretty good in the primary right now... I think the extra day may even have helped!