The border patrol checked each time, searched his person, but could not find anything on him or on the donkey that he was leading.
Finally, one day, when the smuggler and agent were both retired, and having a drink at the cafe, the agent asked him,"I always knew you were smuggling, but could never catch you in the act. Just what was it you were smuggling?"
The retired smuggler took a swig off his drink, and paused for effect...."Donkeys."
So does Walter E. Williams.
http://townhall.com/columnists/WalterEWilliams/2000/08/01/three_cheers_for_smugglers
I forgot to add plastic grocery bags.
I intend to smuggle those as well.