Maya could relabel their products so they don't have recognisable plant names on the packaging, perhaps, to help their customers? What is written on the packaging, such as "Sacred incense seeds" or whatever unrecognisable thing the locals call them, could correspond to the latin name in the description on the website. Once a friend of mine ordered MHRB and it came without the species name on the packet, perhaps to save from slowdowns in customs.
This friend also remembers that one post office worker remarked on how he gets a lot of packages from Amsterdam, so they must be noticeable to staff if you get enough of them and I'd imagine customs are nosier than your local sorting office.
Once my friend accidentally ordered something from Canada that had unbeknownst to him since been banned in the UK. He got a letter asking him to ring customs about it. He just ignored the letter and nothing ever happened.