Comfort is important in chess, so I would grant a little latitude to players, but I personally would like to see a smart or business casual implemented as standard.
I think the presentation and the image is important, as you look you feel !!
I believe that long pants and polo shirts should be the MINIMUM dress code for male players at ALL official FIDE events for adults. I do not believe there is a need for suits and ties unless the event is held at some very special places, and that should be announced well in advance. What do you think?