Sorry John but it boils down to administered or under the direction of a licensed physician Viagra is Schedule 4 so the requirements for scripts are a whole new ball game.
Again do you have a written script in hand when you are given a sample at the doctors office? The answer is no because doctors office samples are Schedule 4 and do not have the labeling requirements that Sched III drugs do. Legally the doctor could have the bottle labeled John Doe as long as the patients personal file in the Doc's office can validate the information.
Your wrong and owe me a beer, I'll collect this weekend