Barry Cooper, ex narcotics agent, shows viewers how to avoid narcotic profiling, deal with drug dogs, etc. NPR article makes it sound pretty legit.
By the time your child is old enough to fit into these, he or she will be old enough to run screaming from you when you present them as a gift. They should really make these for infants and toddlers, who are too young to understand and can therefore be forced into Armor of God onesies.