Abusing people in a service role anywhere is pretty stupid and counterproductive. Restaurants spring to mind where customers abuse waiting staff.
A few weeks ago I had to take my wife to the GP, who promptly sent us straight to A&E with a GP note to prioritise. Never encountered this before, but it was very effective as she was sent straight to charge nurse triage and a young female doctor then saw her pronto 2 minutes later at most. At this point a woman started complaining very loudly about queue jumping, letting everyone know using shall we say fruity language that she is a Traveller and she was being discriminated against. Her evidently dimwit husband joined in proving conclusively that idiots attract.
An older female doctor emerged straight away and spoke to the travellers, very calmly. She said the doctors prioritise emergency care and if they did not behave themselves immediately they would be put at the bottom of the priority list (the woman had a cut hand I think) and any hint of further trouble would result in them being removed from A&E by security without further debate. I got the impression that the medical staff are used to dealing with abusive people and quite rightly refuse to tolerate it.