I remember the yr 12 doing muck ups when I was in yr 8. They wore skirts and had makeup on, it was a laugh.
I go to a boys only school so it was quite obvious but if i was in a co-ed school, man i would have a hard time telling who's who lol. Some guys did it really well i have to admit.
Another time everyone in the class would have their jumpers on, the teacher would be writing something on the whiteboard and one guy would give the signal for everyone to take their jumpers off. The teacher would look back and be like WHAT THE HELL !
. That was 2 years ago, however last year I don't think we had any muck up days only a formal. I think it was up to the year coordinator that year soo.. but nothing bad has ever happen during muck ups