Personally I think this falls under Rigger 5.0's "Special Equipment" (same as dozer blades, snowblowers, etc) because it's equivalent to smaller the smaller water cannons seen on firetrucks, and there are way too many applications for it that aren't hurting people for it to be classified as a weapon. Plus, it would be just like those nasty corps to pack every last heavy machine gun (loaded with gel rounds, of course) onto their riot suppression vehicles and still have plenty of room for water cannons.