Thank you for reaching out to the Constant Contact Community. It's my pleasure to assist you today.
That's a great question. At this time, the Event Checkin app has been retired. We are tracking feedback to bring a form of the app back and I will add your feedback to that request. We are also in the process of doing a complete revamp to the Event Marketing tool and this feature could be in that update. Please feel free to reach out if you need anything else. Thank you for choosing Constant Contact. Have a good day!