It is a common misconception that press gangs randomly seized landsmen from their homes as portrayed in the film. The power of press gangs to conscript men for the Royal Navy was limited by law to seafarers, including merchant seamen, longshoremen and fishermen. Also, a press gang could not have seized Harry. As the eldest son of the local squire, Harry was a gentleman and a member of the landed gentry.
At the end of the film, Dr. Syn and Sir Thomas are discussing Harry's escape from Dover Castle. Dr. Syn mentions that "The Scarecrow" helped Harry when Dr. Syn could not. Phillip Brackenbury was sitting nearby, and had helped Dr. Syn in releasing Harry. If Phillip overheard, it should have told him just who "The Scarecrow" was.