TennisPoint has several different auto-emails:
Auto-Nag Email -- email that is set when the team member's availability is unknown or not sure. This is not on by default but you can turn it on in the "availability settings" in the "set/view availability" page at the top of the page.
Confirmation Reminder Email -- this email is auto-sent every 24 hours (prior to the match) to the players who haven't yet "confirmed" for the upcoming match. This email is "on" by default anytime you send a "match confirmation email". Yes, this auto-email feature can be turned off on the same page you create the "match confirmation email" at the bottom of the page.
Match reminder email -- this email is a "notification feature" for each person's account. They will get the email/push notification about 3-5 hours prior to the match about it coming up.