Frank raises some great points. However, the SEC's current contract with ESPN isn't one of them. With inroads to the Texas market, the SEC would have the clout to force a renegotiation with ESPN. Their leverage would be something as simple as, "Renegotiate with us now or when the current contract expires, we'll go to NBC/FOX/The SEC Network."
Further, if A&M leaves, the Big XII is effectively dead. That will trigger OU's move, Missouri's move, the fracturing of the rest of the North, and needs for other teams to find homes. Which could prompt Mega-Conference talk again, which would effectively nullify current TV contracts.
I would agree that A&M's situation is more saber-rattling than intent to actually move. But it cannot be ruled out simply because the roadblocks seem formidable. Frank and I are basically saying the same thing - that it's unlikely - we're just approaching it from different angles.
I'll admit that my angle is likely to be biased in favor of exploding the Big XII, but the points are still valid.