I can honestly say that it has happened to me only once. In Tampa. Dec 1994. The Rams lost a late season game that was sloppy for BOTH teams. I had one A HOLE following me and my girlfriend down the sidewalk, talking obscene trash for a full block. When we stopped to cross a street, he pointed his finger ON my girlfriend's shoulder and said "You guys suck!" I grabbed his finger and simply told him to back off. It was THEN a crossing Cop told ME to chill!!! I was so mad that my ears plugged. I know my BP was 200/190 ! LOL
BUT.....With that said, I have been to Tampa MANY times as a Ram...Dallas...Miami...Charlotte....Atlanta....Here in Jacksonville.....and even New York (Jets game in 2016) I have been to more sports bars than I can remember. One was even a Bills fan club of 200 Bills fans. LOL I was at THAT place for the 1992 opener vs Buffalo. We lost 40 to 7. All that and I have experienced real hostility only that one time in Tampa.
I have always had fun with other fans. When my team scores, I cheer and don't point at other fans to rub it in. From what I have seen....USUALLY hostility can be easily avoided. I hear places like Philly an exceptions.