Make sure you are double checking your boxes, luggage or anything else a cat might sit in before closing it.
A couple in Utah accidentally shipped their CAT in an Amazon return package. The cat, luckily, was found safe in California after 6 days with no food or water. So how did this happen? The couple was shipping back a box of shoes when the cat made itself comfortable and they didn't realize they taped the box up with the cat inside. The cat had a microchip and when it was found it was taken to get scanned. The Amazon worker kept the cat, until the couple could reunite with the cat.
The cat is back home now safe.
Source: Business Insider