Audio problem: At the bar after the tall black man asks to dance with the boys' dates, he lifts the booth table up off the floor. There's a sound like it's being forcibly ripped out of the floor, yet the table has a round bottom with no visible bolts or screws. While it may have been heavy, it wasn't secured to the floor.
Audio problem: When D-Day, Bluto and Flounder are running out of Wormer's office after the horse died, there is a sound effect of them screaming as they flee the scene. This exact same sound effect is used when the boys run out of the all-black bar, except Bluto and D-Day weren't there; it was Flounder, Kroger and Boon. (00:30:40 - 01:17:15)
Audio problem: When Bluto is using the ladder to look in the sorority house, the ladder gives a clanging sound like an aluminum extension ladder. The ladder Bluto is using is a single frame wooden ladder which wouldn't make any clanging sounds at all.
Answer: He's in R.O.T.C. The Omegas are in the class, too. Military uniforms are required dress.
Captain Defenestrator
That was not a fraternity event. During the sixties, male college students were required to be in the Reserve Officer Training Corps. That required classes and drilling. The fraternity members would get mixed together, just like any regular class.