I am sure there have been cases of demarcation which are usually trotted out to demonstrate 'ancient' restrictive working practices,which were part of that era's downfall according to some;

As a trainee engineer in 1976, I remember changing a toilet roll when on secondment to our Sheffield factory and being seriously worried that someone might find out and accuse me of doing somebody else's job. My predecessor had almost caused a strike by helping to sweep up some rubbish. The union's grip was total, and the atmosphere was poisonous.

http://news.bbc.co.uk/1/hi/magazine/6729683.stm