I'd say as far as Tuesday's concerned, you either find an excuse not to attend, or borrow trousers to attend, since the employer wants to create a particular impression on potential new clients. Maybe not the right impression to win new clients but the boss has made the decision on how she wants to make the presentation and as an employee you should go along with it. I'd continue wearing kilts on other days, but if they do eventually introduce a dress code which bans kilts I'd be tempted to tell them where to stuff their job and they'd lose a valued employee. Hopefully though, long before things ever get to that stage, the top brass will have sussed out the chronic inadequacies of your immediate superior and got rid of her.