Well, I believed to recall to have heared that in one country, i thought it was Britain, pubs now are demanded by law to serve beer in light plastic cups, because too many people got injured every weekend during football time when the rumbles started and the bars went up in a fights and bottles and glasses were used as weapons. I'm still sure that it was not just in and around stadiums. But well, I forgot the details, it seems.
But regarding weapons, nothing matches the glasshammers they use in Bavaria. Those things really are thick in hull, and have some weight!
They don't break easily. There is also a version made of stonewear (? right word?). These can be even heavier (but break much easier when falling on the floor).