No, but there are some pieces of equipment that I use as a "just in case" type of gear. I always use a breastplate on XC, even though I rarely have a saddle slip back. I always use an overgirth on prelim and above XC even though I have never had a girth break. I usually use a running martingale (properly adjusted) even though my horses don't fling their heads up. XC is a rough and ready discipline where KA KA can happen quickly. I would rather be over prepared than under prepared.
If the martingale is correctly adjusted, the horse never knows it's there.