Predicting your running time??

Last Sunday the Ladysmith Striders held an other very successful Cinnamon bun Run were you could run an 5 k.m course or an ten k.m run on top of that you had to guess what you-re time would be to finish .  At the start of the race over four hundred runners were waiting for  the race to start  this was a good showing seeing close to an hundred had,nt  shown up for different reasons mainly I think is of the rain that had been forecast for the morning The entry to race was that every runners had to bring five non perishable food items which were to be donated to the local food bank . To win you had to be as close to your predicted time as possible , No timing device was to be worn by the runners, Although some runners did have ear plugs to listen to music, would this be a cause for  disqualification, seeing that you could win some nice draw prices  if you came on your predicted time. The draw prizes  were laid out on a table with the winner getting first pick. Another thing is if you didnt. hear the announcer announce that the race had started thereby  loosing a few seconds .  Wait an minute this is a fun run  with the participants raising awareness to the needs of the Lady smith food bank, but you always have a few serious runners that are out there trying  to beat their time ,  How about the runners that have no running experience  , how are they going to predict their time with no races to fall back on to see-what their time would be to finish a certain distance whether you-re running or walking   or how they felt the last time they finished a run, It is not easy each race is different some are hillier  some have more switch backs and corners , then you have the long straight road races , they could be five or ten k.m but each one is different, Each race  you run different especially if you dont have an knowledge of your pace when 
running It surprised me hear the results of the  Cinnamon Bun Run some of the results were close to their predicted time, It seemed that the female runners were better at predicting their times then  the male runners , with the Ladies picking up most of the draw prizes .Mt runner did an tremendous amount of work organizing the run and working behind the scene.  I give him all the kudos for that ,