I've had that at least once in the past year and I got my package okay. At least they posted truthful information, which hasn't always been the case.
As for the post office, I recently had a package that was shipped "Two-Day Priority" take 8 days to get to me. I hate to think, if the seller had sent it regular post, how long it would've taken.
And I mailed a card to a friend in England about two months ago - never reached her and can be considered lost by now. No way would they even bother to track it, since it was just normal airmail. It was a special card for her; nothing to be done about it, but very disappointing.
"" A little learning is a dangerous thing."-Alexander Pope