Cardboard is Not a Baby Toy

I purchased a cheap duffel bag the other day to help with the move, and it contained a single piece of cardboard with the following print on it.

A piece of cardboard that says: Attention!  Please remove this corrugated display device.  It's not part of the bag and should be discarded after purchase.  This pop-up expander is used for display only, and should not be used for any other purpose.  This is not a toy, do not put in cribs, playpens or carriages.

Do parents generally put large pieces of cardboard into the crib with their newborn?