It's one thing to say youre a BYU fan, it's another to show it with deeds. Attending games is a great way to show what it means to be a fan. It'd be difficult to say that your a big-time BYU fan and never go to the games. That said, nobody is obligated to be a big-time fan, and there are other ways to support the team like donating to Cougar Club, etc.
Now, all that said... If there was ever a time when lack of attendance really hurt our team, where it's health was beginning to decline because of lack of attendance at games, THEN I think anyone who professes to be a BYU fan should feel obligated to help by going to the games. Otherwise, they should lose the pretense and align themselves with another team beacuse they dont really care.