Question: If someone were to find out about your 5 Day Challenge online or from promotional material with a QR code after the registration end date of your challenge, are they able to register or reach out to us?
Answer: With how the funnel and form is set up, they could still technically "register" by filling out the form on the optin page. In that scenario you would still get the lead in the system and the confirmation email would still be sent to them automatically (with a link to your calendar) but they wouldn't actually get any of the challenge information if the challenge is already over.
So if you ever have someone try to join after the challenge is finished, you could just message them in CBP, explain the challenge has already finished but then invite them to book a call with you if they have questions about their current situation. (as it relates to ICP and DCT).