The Dreaded Dotted Line
Sailor's Beware
Whether it be from willingly joining, being hornswoggled, or getting hit on the head and hauled aboard, every sailor who finds themselves working aboard a pirate ship must sign The Contract. The signature must be willingly made, no matter if the pirate is able to write or not. A blade to the throat, a threat of being made to walk the plank, or any other dire promise is not enough reason to declare yourself having unwillingly signed. Only when someone holds a pirate's hand to The Contract can a signature be considered unwilling and will hold up in Pirate Court. Of course, a pirate capable of surviving never signing The Contract long enough to reach Pirate Court is rarer than feathers on a dragonfly.

by Darkmoon_Art
To help pirates find the right place to sign on The Contract, a dotted line has become a standard addition. Many captains argued against this as they found it much more convenient for a pirate to sign anywhere on the bloody paper. Some further argued that, for those who could not read or write, where they signed could not possibly matter. The Pirate Court, however, insisted that signatures must go on the dotted line as further proof of it being made willingly. They have further decreed that if a Captain has any contracts not signed on a properly placed dotted line, it will be assumed to be forced and they will marked with the Black Spot.
That is a very loose definition of 'willingly', pirates. XD Great answer to this prompt.
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