Highschool was some years ago for me, but my girlfriend talked me into wearing her school uniform to a halloween party. It seemed like harmless fun at the time.
Unknown to me though, she told her friends what she was planning, and two of them showed up dressed as teachers from our school, complete with "Board of Education" paddles. Several others brought cameras. By the end of the evening they had taken quite a few pictures of me in the skirt, the skirt being flipped (by practically all of the girls at the party), and a rather embarrassing collection of pics with me over my girlfriend's knee getting my bare ass paddled. I'm just thankful that this happened before the internet.
Like yourself, highschool was many moons ago for me also but I never had the opportunity to be the wearer of girls clothes at a school party. However in my early years as a teen and in to my mid twenties I would frequently dress as a girl and go out and about. I was fortunate enough to be on the small side, quite slender and with boyish-girl looks, so girly clothes did fit me without any problems. Long hair being fashionable at the time for boys, with makeup applied and a change of hairstyle, Lorne would become Lorna in a short space of time.
In my teen years I always went for the tarty look but later I did dress school style once or twice.