Welcome to the forum Bchickness!
Sorry , I can't really help since I live in mostly wooded, flat terrain, I don't even use the provided belts on mine. But I am interested in why exactly, someone would need a four point harness, in something that doesn't move all that fast? Mountain trails maybe? If so, then we're gonna have to ask for pictures. East Texas terrain is a little boring in that way. Mud, or swamp, is the most exciting thing I'm likely to encounter. Otherwise it's an exciting 7mph. all the way.
In answer to your question though, I'd think that the rock crawling crowd would know. Personally, if I thought that I needed that much safety, I'd want a racing seat, with hard doors, and a net.