How would FedEx employees come to know it's a bomb? Should they open and chemically test every box's contents? YouTube alone has one 300 hours of video uploade

How would FedEx employees come to know it's a bomb? Should they open and chemically test every box's contents? YouTube alone has one 300 hours of video uploaded every minute. How are they to determine whether any of that is infringing on someone else's copyright without error or trampling on Fair Use / Fair Dealing?