I am also a Cowboys fan and have been to Lincoln Financial. I go to Giants games every single year. Always decked out in Cowboys gear.
Clearly, I am also a Red Sox fan. I go to games at Fenway a lot, many of which have lots of away fans there, including one game vs. the Rangers 2 years ago. Even though the Rangers destroyed us, nobody had any trouble, including this one REALLY obnoxious group a few rows down. I have also been to both Yankees Stadiums in all Red Sox gear, and never really had much trouble other than some heckling. It has gotten to a comfort level where I am even okay with my girlfriend wearing her Sox stuff there too.
Most of the s*** like that is all made up. If you travel to an away game and act with class and respect, 99% of the time you will receive it back.