I believe that Demigods should be able to port without their minions. They may be escorting another player, attacking another objective, or healing up at the fountain.
I request that in order to move minions with you on a portation scroll that you must select the minions you wish to take with you. If only your Demigod is selected then only he will port to your destination. Any minions you select will follow and the minions you do not stay where they are located.