Hello @jnwallac 
Welcome to the Canvas Community. Thank you for posting your question. The answer to your question is a definite "maybe". It all depends on the notification settings that each of your students has configured in their own Canvas account. Some students may choose to get notified about course announcements via e-mail...while at the same time other students may only want to be notified about course announcements via text message. It's completely up to the end user. See https://community.canvaslms.com/docs/DOC-10624-4212710344 for more information. I hope this will help, Jamie.
