Watched adress?

If you get something snagged by customs they put that address on a list, correct? So then how would they spot that address again, are all of the address's of incoming mail put into a central computer run by customs? They would have to be able to monitor mail comeing in form all different type of carriars. How does this effect domestic packages?

i thought that to, but i ordered something from overseas and it got snagged. then i ordered a few months later and the order came right through. so, i dont know whats up :unsure: