Some of my faves...
No pirate shall attend a movie with less than an Arrrr rating.
If circumstances demand a career change, a move into real estate brokerage or tax collection shall be considered a lateral move and said individual may keep their pirate status.
No pirate shall ever sit on a toilet seat, for any reason.
Pirate Law: You can't spell pirate, without "irate". There's a reason for that, so don't even try.
No pirate will ever, ever raise his pinky when drinking any sort of beverage.
Under no circumstances does a pirate speak with a Ninja, unless he first decapitates that Ninja and uses his head like a sock puppet.