This is a very basic question. In a couple of days I'm flying to another country and I'm bringing some vitamins with me (Vitamin B, Piracetam, some other innocuous stuff). What's to stop me from just emptying my vitamin C capsules and throwing in some ecstasy tabs or some other banned substance? Sniffer dogs? Do they check the capsules? How do they know that my vitamins are what they claim to be, and not something that may be illegal (in the country I'm trying to enter)? Just curious.