I know what your sayin mate. At BA we have stupid things called in-flight jackets. As thick as uniform jackets but meant to be worn during the service.
Last time I wore mine......hmmm...can't remember!!! Usless!!
Get so hot in it it's like a rainforest underneath my armpits. So....I don't wear it and don't ask my crew to wear it either. But hey that's the advantage of being in charge.
If it's hot...complain to your in-charge crew member. My attitude is happy crew..happy pax...job done.