If they start with BA style, I hope they at least look it is executed and enforced properly.

I hate those ATR flyers who put their small bags and jackets in the overhead bins even if they could easily keep small bag underneath seat and jacket in their lap. Even more they usually put them in a manner to take away lot of space from others. No courtesy. Always difficult to get a real trolley in overhead even if I have selected my all trolleys according to fit exactly the ATR overhead since that is the smallest bin on AY fleet and at the same time qualifies for other airlines too.
Same goes even worse for some DYKWIAs who have maybe titanium card and like to show it dramatically, boarding first in line, seating themselves at prebooked 17C, unpacking veeeery slowly to let others wait in line in HEL -30C fridge.

I am always happy to do the same but with the difference of vanishing into 17C like a submarine in Swedish bordersea
(rant over)