So, who has put random bolts and bits in someone else's parts container, just to mess with them at the end of their reassembly? I think someone tried it to me - I have enough trouble repeat assembling because I forgot to put that part in before this one...
I had an uncle who used to say, "pour the leftovers in the top and let them find their own way back."
i used to do that when friends came over to use my tools, i made sure the parts would resemble something on their bike so it was always a lot of fun (for me)