I believe in order to ship a lithium battery you are supposed to provide a MSDS (or it's some other safety data sheet). Don't remember if it has to attached to the outside or inside.
Yea, I learned not to say anything about "Will ship in 24 hours" or "Will ship asap". I got a buyer who purchased and 5 minutes later asked why I didn't ship it yet. When I did ~1 hour after he paid, he left a 2/5 star for time it took to ship.