Usually if its found by customs you'll get a nice little letter telling you that a suspicious package sent to you was intercepted by customs* *If it contains marijuana seeds, schedule III or V pharmaceuticals, or legal research chemicals I rarely hear of interceptions so on't have a particularly large sample size to go off of, but I can't recall hearing of anyone getting a love letter for something like MDMA or LSD. The majority of love letters I have heard of are for anti anxiety drugs and viagra.