TSA doesn't mind, I have seen people ask outright. HOWEVER Air Canada still bans them.
I have mailed my circulars to myself in past, if my flight originates on AC and I don't have checked luggage.
And if you are on an AC flight leaving the US, they usually don't mind. (Was at Dulles once, and a woman pulled out her knitting and the counter staff didn't bat an eye. I was drooling, since mine was sitting in my packed luggage because I was on an AC flight)