Having active ABS when towing ON THE road is dangerous also. I know somebody who experienced that first hand when towing 3000 LB boat with his 96 4runner 4x4.
This thing just did not want to stop from relatively low speed 40 miles before an intersection.
He avoided crushing in to the car in front of him only because extra space on the side of the road.
He swears his ABS system is off for good.
He removed the fuse. I think he gets ABS warning light lit on the dashboard.