A form of biological warfare.. Even throwing them in the garbage, they could potentially grow there and do harm as well.
China is not playing.
"Virginian authorities have warned that the seeds may be an invasive plant species, which they say could wreak havoc on the local environment by displacing or destroying local plant and insect life, as well as crops. The state’s department of agriculture and consumer services has urged anyone who receives the unsolicited seeds to contact the Office of Plant Industry Services."