If I were Vandy, I would think I'd love to go to the B1G. Out of all the major conferences, I don't know if a single team fits in less with their conference brethren than Vanderbilt does.
Vandy is a prestigious academic university who is not very athletically gifted, playing amongst a whole bunch of deep south football schools. They just seem like such an odd man out there. Even the ACC would be a vastly better fit for them