As for flights, I have heard announcements from the cabin crew instructing passengers not to use perfumed products on the flight as they have a passenger on board with a severe allergy. Ditto instructions to refrain from eating nuts or opening packets of nuts. They would be in big trouble if they failed to make that announcement having been informed by the passenger in question if they had an allergic reaction.
You can assume this only happens in cases of very severe allergies where anaphalactic shock occurs, which can result in death.
I do not know how such people cope in many public spaces, but they do have a right to work and travel within reason. Suggesting that being asked not to wear perfume around them is rude is a bit strange.
Personally, I think that the airlines stopped serving peanuts in order to save money not to prevent allergic reactions from passengers. Back in 1987, one airline removed an olive from each dinner salad, and it saved $400,000 per year. I can't imagine how much money they're saving from not serving snacks on-board. However, they seem to have no problem bringing the beverage cart around multiple times. When I flew in March, they brought me coffee two times and club soda another two times.