I worked in A&E for six years.
It was definately not just 'underclass types'
who were a problem.
The majority were drunk but getting pissed is not the preserve of the lower classes.
The main reason, apart from the drink, was the amount of time people had to wait. Sitting in a cold waiting room with other pissed people, on nailed down chairs just increased the tension.
I dont condone any violence against staff obviously but I could see why people got wound up.
They attempted some safety measures when I was still there. They put a sort of plastic gaurd round the reception desk. Only problem was it was high enough to impede communication but low enough for someone to reach over and clap you one if they felt like it.
I had guns pointed at me, was threatened with rape, stabbing etc. It was a daily occourance. As a receptionist I was blamed for any delay and accused of doing it 'on purpose'.
This was before triage was introduced, it did get better once they got to see a nurse within a few minutes but not much.
There were the regulars who wanted to be admitted. The psych patients who had to wait 10hrs plus to see a psych, diabetics who were having hypos and who were terribly embarressed about any offence once they were sorted, people who complained because they thought it was 'first come first served' and got pissed off that someone went infront of them (even if that person was having a heart attack).
It was certainly and interesting job 