From the Columbus Marathon website http://www.columbusmarathon.com/race-information/walkers:
I'm excited!Competitive Walker Division RulesAll participants in the Competitive Walker Division must wear a special sticker on the front of their shirt and a special bib on the back of their shirt on Race Day. Judges will be located on the course. Any participant in the Competitive Walker Division seen running will be ineligible for Competitive Walking Division Awards.The Competitive Walking Division stickers & bibs can be picked up at the Competiive Walking Division table at the Expo. This table will be located next to Number Pick-up. ONLY those walkers interested in competing for awards must wear the sticker & bib; walkers taking part in the marathon and 1/2 marathon who are not competing in the Competitive Walking Division do NOT need a sticker or bib.Following the Race, all participants in the Competitive Walker Division will be required to write their name and race number on their back bib, and turn it in to the information table in Celebration Village for verification. Those participants who fail to turn in their bib will be ineligible for awards.