Seems like this phenomenom have now a formal name: BRUSHING
(translated with google...)
How the 'brushing' technique works
Why do these prioducts arrive? That they are seeds makes the situation quite peculiar, however the reality behind it is much simpler. Everything seems to indicate that some sellers are trying to better position themselves on e-commerce platforms such as Amazon, Alibaba, Etsy or eBay. For this they use a technique called brushing.
The brushing technique allows Internet sellers to better position themselves on the platforms where they have their products. It is no secret that having good reviews and ratings as a seller makes stores give you more visibility and that users trust more to choose you as a seller. Therefore, it is a matter of creating false valuations. However, many of these Internet stores do not allow you to leave ratings unless they come from a user who has received a package.
Said and done, some sellers have started shipping products for free to random users and leave positive reviews on behalf of these users. They have probably obtained the shipping addresses and other data from leaked databases or simply from finding them public on the Internet. (watch with this guys)