2 of our ride parners do full marathons, Tammy and Aimee. Tammy had a bad experience with the lines on the road. Either they were wet and she slipped or she tripped on a reflector (center of lines). Either way , she fell and hit her face on the pavement. Only hard enough to bruise without any serious damage thank goodness.
But be careful out there. Watch your step and don't get forced into a bad position. Watch the wet lines and pavement at the water stations too.