I guess it would have to be a case by case basis. If we assume an “ISIS bride” is someone that was not originally in ISIS and was indoctrinated and married an ISIS fighter, then you have several issues in play if/when they decide to try leaving that life. Was she actually a fighter? Did she commit crimes? Was she a violent threat? Was she participating in illegal activities for ISIS that did not involve actual physical actions? If the bride lost her husband and had done nothing wrong and realized she didn’t like ISIS, she could try getting out. There would be no reason to put her in prison since she had not committed any crimes. However, due to ISIS having a past history of planting operatives to be activated later, many places are leery of just accepting ex-ISIS members as immigrants, treating them as refugees instead.