I did a duty at my local Parkrun yesterday we had over 230 runners and a problem. I counted at least 5 runners who crossed the finish line and then took off saying "I forgot my barcode" and at 5'1" tall I'm not big enough to wrestle anyone to the ground It's all very well running but if a runner doesn't go into the funnel and get a number token (I assume all Parkrun's have the same system) then get their barcode scanned it throws the times and numbers into utter chaos and then some poor person has to try and sort it all out. Hence sometimes the delay in getting results out to all the runners. At least if you go to the scanning desk and say "no barcode," they can log it as such.
So please, please, please take your barcode's with you. Parkrun is a wonderful event, run by volunteers who give up their Saturday morning to do duties and also give up the chance of being able to run which is very generous by any runners standards. Don't take it for granted that there are always enough volunteers either, some weeks our venue is still trying to get all stations covered as late as Thursday evening.
Sorry if I sound as though I'm preaching but I promise you will enjoy doing a duty as much as you do running and you will have put something back into what is after all a free event.
Here ends my sermon of the Parkrun volunteer's group and thank you for reading, if you have!!