the charge isn't carelessness, it's importing 31 kilos, which is nearly 5 stone in old money. If he really had that much at home, then being caught with 3 grams on him wasn't carelessness, it was industrial-strength stupidity.
Honestly, what an idiot. Still, when you see some of the pathetic sentences we hand out in this country for far greater crimes, I hope nothing too bad happens to him.