I was sniffed by a rather spiffy dog! She gave me the nod and said I smelled OK!
They went through my hand luggage, too. Very embarrassing having your smalls examined in the ferry terminal!
However, if that's what it takes to prevent drugs getting in I'm happy.
Othere than searching all of us every time, I'm not sure how you prevent these things... the amount in CP's case is 150 grams... less than a bag of sweeties, but enough to ruin a few lives. I can think of dozens of places to hide something like that and I am sure drug couriers are far more creative about it than I am.
However,the police are also smart, and some of them DO get caught, even when they have swallowed bags of stuff, or put it in unmentionable places.