hat
EDIT: Somebody just said that writing on money might be illegal, can anybody confirm this? I'm googling around right now.
It is not.
Yes, it is called Mutilation of national bank obligations
United States Code
TITLE 18 – CRIMES AND CRIMINAL PROCEDURE
PART I – CRIMES
CHAPTER 17 – COINS AND CURRENCY
§ 333. Mutilation of national bank obligations
“Whoever mutilates, cuts, defaces, disfigures, or perforates, or unites or cements together, or does any other thing to any bank bill, draft, note, or other evidence of debt issued by any national banking association, or Federal Reserve bank, or the Federal Reserve System, with intent to render such bank bill, draft, note, or other evidence of debt unfit to be reissued, shall be fined under this title or imprisoned not more than six months, or both.”
However, that shouldn't scare you. Legality exists to continue your enslavement. Submit or not.
By possessing papers that have graffiti on them does not imply that the defacement was by the current possessor.