It was a mix on the Magic too. Dinner that night was formal, and since we had late seating, we stayed dressed up. No big deal either way, it's basically an informal party.
Only time I ever say anyone under dressed anywhere the entire week was in the dining room. A couple several tables over from us wore sweatsuits one formal night, and shorts for the second.
But they always seemed out of place, I don't think they got out much. He was always sending food back, I suspect he was a guy that normally ate meat (plain) and potato.........he seemed lost when served meat with gravy on it!!!