My understanding is there's a difference across US Postal Service, FedEx, and UPS (correct me anybody if this is outright wrong) - which is it's illegal to ship alcohol via USPS whereas it's policy of UPS and FedEx to not ship alcohol unless you're a licensed alcohol purveyor (not a violation of any law because they are private shipping services). FedEx and UPS can and presumably will refuse to ship a container known to them to contain alcohol. As others have said, I dodge the concern by using some partial fiction or omission of facts when declaring what's in the box. I pack bottles carefully to avoid possible breakage that would reveal the contents. It feels a little awkward to me when the ship-to address is a brewery, which is often the case for competitions, and in addition the address information the competition requires may contain indication that it's going to a competition. There are work-arounds one can figure out for this. If you want to bother, possible fictions here include saying you're shipping yeast samples or hops samples for evaluation. I've had FedEx staff basically give me a "wink and a nod" reaction when shipping in such cases - they satisfied their company's requirements for asking, I gave an answer, they and I know what's in the box, no further discussion.