This is such a stupid thing to be worrying about. The world is falling apart around us and we are debating hats, shoes and rucksacks. It is their train set - just get on with it and worry about something else. It takes an absolute minimum effort to comply with the EK dress code. In some ways you have to go out of your way to break it. I am not a company man at all but they pay the money so when I am on company time and in company property I will make the effort and put on a pair of trousers. I mean really why not. Boots in the cockpit? Why bother ?