This would not fly in this case because you have a multi-state pact so sovereign immunity would not exist.
I've seen a number of lawyers comment on this. This is a popular idea with some fans but would not hold up in court.
There is a reason no school has been willing to try to get out of a GoR in any conference that has one. They are all basically written the same way and are all written so that there is no exit mechanism. To get your rights back you are going to have to sue and there is a high likelihood you might lose that suit, not to mention the legal fees will be high and would likely take years to litigate without even knowing if you can win.
USC, UCLA, TX, OK all left without trying to get out of the GoR (TX and OK ultimately came to an agreement with the B12 to pay them $50M each to get out 1 yr early).
Every P5 school that has switched conferences has done so when it was not under a GoR or it was about to end.
If you take OK and TX as the likely baseline used in any future negotiations (B12's contract is worth less per team than the ACC's) that would mean an ACC school is looking at $500-600M to buy itself out of the GoR and exit fee at this time. Maybe that is what FSU is thinking (though I doubt it, I think they somehow believe they are magically going to get out of it) with trying to raise private equity funds.
The other issue few seem to think about is what is in this for ESPN. ESPN would not want any school going from the ACC to the SEC as it would mean paying more money for the same program. I suspect if SEC tried to add any school from the ACC ESPN would likely tell them that they would not get a full share for that team (unless SEC has a pro rata clause in that contract - in which case I expect ESPN would still strongly discourage it).
Of course the biggest issue of all is still that viewership models are changing and both linear and streaming companies are trying to figure out what it means for their futures. The linear channels simply do not have the money right now to pay conferences for new members at Big 2 share levels.
I have read that the legal venue for disputes about the ACC or GOR in conference documents is Delaware federal court. I have read that the SEC does not have a pro rata clause like the ACC or Big 12. (Probably because ESPN doesn't want to pay $80 million a year for any additional schools, since only ND could be worth close to that.) Whereas, perhaps in the past, ESPN was willing to agree to for schools added to a conference paying $30 million a year would probably be worth close to that. (That may have been true for the three PAC 12 schools the Big 12 just added, although I read they are on a discount plan for a couple of years.)
I have not read a crystal clear answer on this question, but I believe the only way to blow up the GOR is for the ACC to dissolve. I have read that that would take 8 of 15 schools. I have also read 10 of 15 schools. I have also read that it would be difficult to 8 schools vote to dissolve, because the very act of calling for a dissolution vote is considered a demonstration of hostility and therefore any school calling for it would lose their vote but not reduce the number of votes still needed (or, at least, the first such lost vote would drop the vote to 8/14, the next 7/13... but you are losing "pro votes" so you can't win). I have also read that the diabolical way around this is to have a meeting where the "exit votes" form a majority - like, the 8 schools get on a call, declare a quorum, and then a majority of the schools present vote to dissolve. I cannot freaking imagine such a vote would pass legal muster.
I am not sure that the ACC by-laws are public (*see below), though they may be in a Harvard case study somewhere that was posted on the VT boards.
I found it interesting that the FSU trustee said that their lawyers had been all over the GOR and that "that document was not going to be the reason they couldn't exit." I suspiciously read that as it is the By-Laws document that they have to work through / around.
Article re: Big 12 By-Laws and the "impossibility of nefarious dissolution"
ACC By-Laws
I don't see anything in here about "deemed to have withdrawn." Dissolution is not mentioned in the By-Laws, including as a super-majority item. So maybe it is a 8/15 item. The discussion of a quorum suggests that if two-thirds of members are present (10/15), then two-thirds can vote (7/15). However, the agenda has to be circulated, so I cannot imagine that a "quorum only" vote on dissolution can occur.
I don't see anything that suggests that 8/15 cannot vote for dissolution. But I've never seen anyone clearly in the know stating what the reality is.