What I meant is that if Notre Dame leaves alot of the schools will start looking elsewhere. I know everyone says the Big East caters to Notre Dame, but I think in reality they are the school that is trying to hold everyone together. I really think they honestly like the conference and would like to see it succeed. After reading how the ACC was starting the rumor of Notre Dame going there, I see that they have said they are perfectly happy in the Big East. I really think the ACC is going to be stuck now with a school they don't want.
While I don't think the ACC was necessarily starting rumors (just being stupid in pursuing a pipe dream for some presidents), I agree with you that they're likely to end up with a school that was clearly not among their first line of favorites. (My front runner is Temple.)
As for ND holding the BE together, you may be right. I believe that the Irish football fans want things to stay as is, allowing them conference affiliation for what they need (bball and Olympic sports) but also allowing them freedom for football. And yes, I will concede that if ND does abandon the BE for good, it will limit the potential of the BE conference to the point where the Big 10 or ACC could lure another school away. The question then becomes, is ND's ideas for the BE conference the best view for the BE?! :-/