They are more likely to bend or buckle then break when welded, but you really need to be doin something fun to get to that point. As for repair, a BFH and a little heat should take care of it.
It comes down to how likely u are to damage your sliders and with how much force. If u break the bolts, your sliders will be less damaged but body damage may be done. If they are welded, you have a better chance to protect the body but will need to cut a grind to replace the sliders.
IMO weld it, sliders are cheaper to replace then what could be a lot of body repairs.