Conferences don't cut schools loose.
Once they're in, you're stuck with them until they want out (or violate the conference by-laws).
The hoops only schools will be Big East members until they don't want to be, which will most likely be long after the football schools decide to run away from them and form their own conference.
Correct me if I'm wrong, but I remember some conference required all its members to carry or start a football program within a certain number of years...(the name is eluding me at the moment) causing some of its smaller member to find a new home elsewhere. Still it isn't like SMU, UCF, and Memphis are going to try to kick out Georgetown and Villanova.
I believe it was Conference USA that required all of its members to have football. C-USA had non-football members from 1995-2005 such as DePaul, Saint Louis, Charlotte and Marquette. But DePaul and Marquette joined Louisville, Cincy and USF in leaving for the Big East, while Saint Louis and Charlotte left for Atlantic 10. C-USA added schools with FBS football to have 12 full members that sponsor football.