An assembly configured to detachably attach to a high-chair includes a harness assembly comprising a pair of shoulder straps, a pair of waist straps, a crotch strap, and a buckle. The crotch strap comprises a first end configured to attach to a front portion of a seat of the high-chair and a second end secured to the buckle. The shoulder straps and waist straps are detachably attachable to the buckle. Each strap is formed of a fiber-reinforced, silicone coated material. A harness assembly for an infant seating device includes a strap hub comprising a front portion and a rear portion connected to one another, the front portion having apertures through which the shoulder straps and waist straps are routed, the strap hub being configured to be positioned through an opening in a backrest of the infant seating device.