What is the point of tying a roast with twine?
Generally the purpose behind tying a roast is make the shape of the roast consistent in thickness so that it cooks evenly when roasted. Since you are using a crock pot there is absolutely no reason to leave the roast tied. It will actually cook better and be more tender if you remove the twine. It won’t hurt it to leave it tied, but it will be easier to handle removing the twine while it is cool, than when the roast is really hot and dripping.
