I doubt that is the persons only job. She might be the costume person or in charge of continuity. It's like how the union guys who are in charge of moving everything (teamsters I think) won't let you move anything
It depends what you're moving - and for good reason. Unions remain strong in industries that continue to have dangerous work environments. Film sets are controlled chaos with very high powered electric lights/equipment, cables and cords everywhere, and sometimes uniquely unusual (read: dangerous) work demands - high ropes, scaffolding, helicopters, pyrotechnics, intentionally crashed cars and other practical effects.
When I was starting out in the industry - before I was Local 600 (camera dept.) - I think I scoffed a little bit about the "my job"/"not my job" stuff; however, in most cases there are some legitimate safety/efficiency/equipment protection requirements backing those decisions.
Not only that, with a large group of people you can't trust everyone to have the judgement to tell exceptions to the rule. So it works better to just have everyone learn a simple rule like "don't move anything"
