When you import guests or after guests register for an event, they are automatically subscribed to event emails. While a guest can unsubscribe themselves from email communications, you can also update this in their profile.
To unsubscribe a guest from all event emails and invitations:
Select Unsubscribe Guest from the Guest Options dropdown.
Confirm your choice.
You can tell a guest is unsubscribed by the "no email" icon beside their name.
You can resubscribe the guest to email updates by selecting Subscribe Guest.