Sir Gareth and Princess Lyonesse happily entered the place arm in arm, the costume designs something of a compromise in interpretation regarding 'accuracy about an extremely important period in mystic history,' but Kristoff believed Maxine, with all the help he could give, had done incredibly. And, of course, Sir Gareth's armor was in some ways a decorative modificaton of his own. The last time he attended a proper masquerade, someone died. He's not walking into this place without his gauntlets on.
He also appreciated that Maxine had let him declare it Gareth and Lyonesse. Launcelot and Gwenevere were much more memorable, but he wasn't dressing up as a traitor.