Ah hah! It appears some of the medals went missing - this was posted on the website today:
"We've found the missing medallions! If you didn't get yours on Sunday, email your name & address to *email redacted* (unless you submitted it when you finished) and we will get them in the mail to you right away!"

and this

"Our SINCERE apologies to those who didn't get their shirt or medallion! We will be tracking down the missing items and if necessary, reorder both shirts and medallions! We thank you for your patience, and will get your missing items as soon as we can."

It is a charity run -- in addition my team mates raised funds for Team in Training. It looks like the race organizers will be sending out a survey. I wonder if I'll get one, I was registered, but didn't participate.