I wonder if they're using the seeds as a distraction to smuggle in something else.

Say they send out 1,000,000 packets...999,000 are random seeds to random addresses, but 1,000 are super secret smuggle stuff. When the smuggle stuff gets to customs, they'll say "Oh gee just more packets of seeds like the last 999k." and they won't check it.

Pretty smart actually. Like what drug smugglers do - they'll send a train or convoy of trucks. 9/10 of those train cars or trucks in the convoy contain legit goods, but it's all set up to make the 1/10 car or truck in the covoy that has bad boy stuff look legit.