I've never seen anyone "glassed." That type of behavior would probably be greatly frowned upon.
I have seen people "canned." In the early 90's at an outdoor festival in my home town, the band Too Much Joy got involved in a beer can fight with the crowd. It escalated into involving full cans (not as much of a waste as you’d think – it was mostly Bud Light and Keystone Light from the frat boys).
I’ve been told that “canning” is done in Chicago (using empties) as a sign of approval like spitting on the performers shoes in some parts of Europe.
This seems counterintuitive to me.