Sometimes they shoot themselves in the foot with delivery estimates, too. A month or two back, I ordered an item on Wednesday that said it wouldn't be delivered until the next Tuesday. I was OK with that, so I ordered it. Checked on the order the next day and it now had an expected delivery by Saturday at 8PM. Saturday at 8:01PM it changes to "There's been a delay, now expected Monday by 8PM". Monday 8PM rolls around, no package, and it changes to "Tuesday by 8PM".

So it arrives on the day it was originally expected. Difference is, now I'm irritated because I've had to change my plans several times.