If you’re a drug smuggler you’re in a big money business. Checked bag fees shouldn’t be a binding constraint. And buying business class, which comes with more checked bags, is almost always more expensive than paying checked bag fees.
So when drug smugglers and their money launderers are said to be buying business class tickets for the greater checked bag allowance it sounds like the travel management challenges at any big company, where employees are looking for greater comfort and justifying it based on the needs of the business. Drug lords have travel policies, too, and their mules have to try to stay in scope!