I am a Yale College '80 and Harvard Law School '83 alumnus. Whenever I am asked, "So, do you root for Yale or Harvard at the Game?" I first say, "You silly, the law schools don't have football teams, colleges do!"
From 2003 to 2011 or so, I was President of Harvard Club of Hong Kong, where I was living at the time. I was also a very active member of the Yale Club of Hong Kong. Some years, Harvard Club of Hong Kong and Yale Club of Hong Kong would collaborate a "Game-watching party". Given the time difference, it would typically be in the middle of the night or crack of dawn in Hong Kong.
We, the Clubs, would jointly rent an auditorium. On one side of the aisle would be seated Harvard alums, and on the other Yale alums. Since I was President and thus the official organizer of the Harvard alums, I would make sure every Crimson was all seated on the correct side of the aisle.
Once everyone was seated, I would get out of my Harvard seat and literally cross the aisle and join the Yalies to cheer for the Bulldogs against the backdrop of boos and chants of "traitor", "double agent", etc. I would just laugh it off and shrug it off with the presumed understanding of both sides. Like I said, Yale College has a football team, but Harvard Law School doesn't!