I was watching one of those police specials they have on TV here and it showed the police going up to a person's home and knocking on the door. When the guy answered the door they asked for his name and then showed him that they had proof he had imported seeds. He had a few plants growing that looked about a month old. It seems like they intercepted his order and let it through before going to get him a month later. There is no other way I think they could have known. It's not like the card company would give out info on sales.