Wrong. Almost every screener encounters (possible) explosives at every checkpoint on every shift. Through continuous daily on the job training, every TSO is an expert at handling unknown explosive items.

They find 16 ounce containers of the (possible) high explosive Dihydrogen Monoxide, pick up this unknown (possible) explosive with their bare hands, then dispose of this explosive hazmat liquid by dropping it into a trash can full of other unknown explosive items including toothpaste, snowglobes and cupcakes. Then they stand next to this trash can full of (possible) explosives for the rest of their shift.