Fed-Ex is the biggest drug courier in the world according to my Fed-Ex guy. I think the US Post office is, but we aggree to disagree.
Fed-Ex isn't the one you have to worry about. Customs is. They have the power. They yank any package they want and take a look.
I was just talking to my Fed-Ex friend the other day, and he told me what he was told by the customs guys that used to work in their receiving centers.
He said that Custom's guys look for packages of a certain weight coming in from certain destinations (don't ask me where), packages that smell like coffee (huge tip-off), and packages with any kind of masking smell. They work their dogs through. Their dogs are not trained for Steroids - at least to my knowledge - so you are safe as long as customs doesn't randomly rip open your package.