It is in this nonsense somewhere. I read it a few months ago and haven't dug out the exact reference.
http://www.portal.state.pa.us/portal/server.pt/community/pennsylvania_liquor_code/18291
I reread some of it and there is an exclusion for competitions.
Possession or transportation of liquor or alcohol
(2) For any person, except a manufacturer or the board or the holder of a sacramental wine license or of an importer's license, to possess or transport any liquor or alcohol within this Commonwealth which was not lawfully acquired prior to January first, one thousand nine hundred and thirty-four, or has not been purchased from a Pennsylvania Liquor Store or a licensed limited winery in Pennsylvania, except in accordance with section 488 or the board's regulations. In addition, it shall be lawful for anyone to possess miniatures totaling less than one gallon purchased in another state or a foreign country. The burden shall be upon the person possessing or transporting such liquor or alcohol to prove that it was so acquired.
Notwithstanding this section or any other provision of the law, wine may be produced by any person without a license if the wine is not produced for sale and total production does not exceed two hundred gallons per calendar year. Wine produced in accordance with this clause may be used at organized affairs, exhibitions, competitions, contests, tastings or judgings if it is not sold or offered for sale.