If they show someone in medical garb and they don't come out and say "I am a doctor" they are almost always actors and there is no false advertising.
If they start saying "We asked Doctor Benjamin Pills" And cut to a man in medical garb he may or may not be Dr. Pills. They didn't say this is Doctor B. Pills they just said they asked the good Dr. so it is 50/50 and still not a false statement.
If they cut into the person and the say "Hello I am Dr. B. Pills and ..." That person should be Dr. Pills and if not it might be false advertising.
Remember that just because someone is a Doctor that doesn't mean they are any more honest or that they have ever actually used the promoted item.