I believe this settles this debate once and for all! It's ok to cheer other teams on while attending a different sporting event. However, we in New England have rules on this.
1. You can cheer a Yankees or Colts loss at any New England sporting event.
2. You can cheer a victory of another team as long as it is another team from New England and as long as you are FROM NEW ENGLAND!
3. It is especially acceptable if said event is a playoff victory!
4. As long as you are a "Real New Englander", you can do anything you damn well please!