I had that happen twice at school... I got to my 
mailbox to find a flat package that had been 
rolled up and crammed in the tiny dorm mailbox.  
Both times I had a near heart attack.  And both 
times, it wasn't actually cels in the package 
^^;;  Though I have a predisposition to being 
worried... the second cel I ever got arrived very 
damaged due to poor packaging, and I've been 
paranoid ever since.