Premier League Campaign on the Dangers of Pyrotechnics at Football Matches

The transcript discusses a growing trend of using pyrotechnics at English football matches, which authorities are increasingly concerned about. A specific incident at Aston Villa's home game against Tottenham is highlighted, where an assistant referee was struck by a flare. Despite the risks, some fans view pyrotechnics as harmless entertainment.

When did the incident involving the flare occur?

What do those who use pyrotechnics at matches often describe them as?