Read the very next paragraph of what you quoted. The paragraph starting with "Thank you!". It's instructions on how to get your pin ticket validated and thus confirmation that your c card was properly recorded.
Thank You! To show our appreciation for dedicated volunteers, once you have completed an
assignment you are eligible for the special Comic-Con 2022 volunteer pin! You will get a pin
ticket with your badge and information on where and when to get your pin. This ticket is invalid
by itself and must be validated by Daily Volunteer Department staff at the validation desk in
order for you to get a pin. After you have completed your first assignment you may get your
validation from the desk and get your collectable “thank you” from all of us at Comic-Con. We
are grateful for your support of Comic-Con! We hope that you will enjoy volunteering your time
with us and being part of the huge effort it takes to put on a convention like Comic-Con"
This is what I see when I pulled up the volunteer info. I have to say I didn't read all that. I can't really say this is what I went by when I went for my pin. I may have heard an announcement when I was on line for my next day's assignment. I will say the instructions are a little confusing (IMO), but it does imply you need to go back to Volunteer HQ at some point.