I've never thought of PC as a soft material but then, I've never been walloped upside my head with a beer mug. According to this article in the BBC, pub owners in England need to stock up on polycarbonate mugs if they don't want to face a loss of their liquor license. The shift from glass is to stop the rowdies from "glassing," a pretty nasty term for using a glass mug to attack someone.
I'm not too particular about the material used to make the mug but I sure am fussy about the company I keep. If you drink beer, do so responsibly; stay away from violent fools.