This article shows you, the admin, how to turn automatic self-check-in email confirmations on and off. By default, all profiles checking in on the public check-in page will receive confirmation emails.
On your dashboard, hit “Alerts.”
Under “Outbound Alerts,” click “No” if you don’t want people checking in to receive email confirmations. Note: the default option is "Yes"
Click “Yes” if you do want email confirmations sent out. However, make sure that all the profiles under “Lists” have email addresses. If they don’t have an email address on file, no email will be sent.
This setting is not available on iOS