We're always fortunate to have people like you who, even though you didn't attend the university, are dedicated fans of the football team. A similar argument could be made for parents of football players who started attending games, then kept with it after their son graduated. Technically they didn't attend the university but are still part of Owl Nation.
That said, I do think that a majority of the people who attend FAU games are affiliated with the university in some way other than purely geographical. Ultimately we hope to pull those people in and make this "Palm Beach County's team" and have people say, "Well I live near Boca so you kinda have to be an FAU fan" but of course we have a lot of work to do, both on (bowl games) and off (marketing like we're the biggest and most important team on the planet) the field, to get to that point.
Having a "rally" game like the Miami one undeniably helps building community interest, though it would be way more difficult to convert fans of UF/FSU than, say, Boise State, because you run into UF/FSU people/plates/shirts down here all the time plus the game is close, whereas you never see a Boise State fan, a Boise State shirt or make regular trips out to Boise. So being a college football fan in Boca it's easier to switch from Boise to FAU, especially if they're playing at different times.
And in general it's easier to be a fan of another team that never interacts with your team so you don't have to sort out your loyalties come gameday.