The trick is that they were using speakers as their conduit. The exact brand of speakers were not known. With that kind of flake floating around you would hope that they would use something audiophile grade like a Wilson or Revel but you could also understand if they tried to get past customs with an Israeli product like Morel. Other fear that they smugglers used some of those white van "we just finished a nightclub a few blocks away and have some extra speakers that we can sell you really cheap" speakers and that was how they got caught. Then again, those drug sniffing dogs always help too.
An unnamed AV industry source points out that there are a number of audiophile speakers that actually have more profit margin than 238 pounds of Peruvian flake.