A safety belt is how it sounds, a single strap across the lap. A safety harness has multiple buckles or points that make your little one more secure. Three-point harnesses are pretty safe, including a middle strap that goes between the child's legs and attaches to the belt. A five-point harness is the safest and normally used in car seats. This one has the straps that come over the shoulders and buckles in as well. Any type of high chair or seated function should have at least some sort of safety belt. This is necessary to prevent children from falling out, tipping over and other accidents.