Actual T-shirt on a college student

I couldn't pass up the opportunity to highlight this T-shirt I saw yesterday:

Stupidity is not a crime.
Your free to go.

I can't decide if the grammatical error* is sly and subtle, or incredible and ignorant.

Call me cynical, but I'm voting the latter. I've graded too many papers, read too many essays, and made the acquaintance of too many college students who thought they were smarter than they were.

Heck, I was one, once.

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*"Your" should be "You're", the contraction of "You are". After all, "free" is an adjective or a verb, and not a noun.