marathon question

This year will be the first time I am running in a marathon. I have a question about the running bib: I know a lot of people wear layers to the race and shed them as they run. If I want to wear a warmer shirt to begin the race, will I need to put the bib on that and then take it off and re-pin it when I change shirts? Hope that makes sense...
Good luck to everyone who's running!

No! Put your bib on the shirt you will end up in. When you enter your corral they will check to make sure you have your bib and you are in the correct corral. All you need to do is left your sweatshirt up to show them.

Good Luck!!! See you there!!