There has been some developments in that story. While it's still a bad idea to plant random seeds you never ordered but recieved in the mail (even if it's not deliberately sent for that reason, it might still be invasive where you live), it seems it's deemed to be more likely to be online review scams and not ecological sabotage. To get "verified purchase" status for a review on Amazon, Alibaba or other similar sites, you usually need proof that something was purchased and sent, so they send any random junk they have (or sometimes empty boxes) to an address that's on lists of leaked addresses.
It's called "Brushing", as one of the cheap item that is often sent is an hairbrush. https://en.wikipedia.org/wiki/Brushing_(e-commerce)