No, sway devices are not intended for use when towing 4-down (which is what I'm assuming. Or are you using a trailer?). If the toad wanders, increase the caster setting on the front axle. Also be sure the tow-bar's angle is within spec. You may need a drop adapter to keep the angle down.
2000 Ford E450 V10 VAN! 450,000+ miles
2014 ORV really big trailer
2015 Ford Focus ST