That to me is the issue, the fact that they are not going to abide by their contract. That would be an issue to me regardless of what the contract was. If I were recommending somebody for the job, I would be vouching that they would honor the commitment they have made. If I know they do not have the intention of doing so than I cannot in good conscience recommend them.
.
Unless you are the Amazing Kreskin, you cannot possibly know what someone else will or will not do in the future.
A reference is a reference, not a guarantee.