Good point. The problem is which laws; U.S. state, U.S. federal, U.S. Customs? And for the foreign traveler, there are all the national and customs laws for each country. And there's always the locally constabulary that one may unintentionally tick-off, causing them to find any way possible to make your life difficult.

My hope was to find a way to transport meds, in some more efficiently packed container than they were dispensed in, in such a way that no reasonable authority could question them. I think the second label attached to whatever container would do the job.

As for the doctor dispensed samples, no idea. Those samples don't always come from a doctor (I had an office assistant tell me how she carried sample meds in her purse to hand out to friends, this is greatly frowned upon in the medical profession). Might be just fine... Dunno'.