You can send notifications to the app, which active users with internet access will receive. The app must be opened periodically or be in active use to receive the notifications.
Please note: Users that do not have internet access or are not actively using the app will not receive the notifications. We recommend using additional notification channels such as email, social media, and text messaging.
Understanding the limits of push notifications https://peasi.com/2018/03/20/push-notifications-for-emergency-alerts/
Typically, each registered attendee has a unique email address associated via the registration system. Attendees should be receiving emails from you directly and independent from the event app or notification settings. Professional attendees are likely to keep checking emails regularly to keep up to date with work emails and would be receiving your emergency email.
Twitter acts as a great news feed aggregator and is a fast solution to send emergency information. You may have users actively following your Twitter feed using apps on their devices. EventPilot users will see your tweets in the activity feed on the home screen, so even if they have notifications for the app turned off, the information would be pulled into the app.
If you collect cell phone numbers during registration, an SMS text message is a great way to communicate emergency information.
True app Push Notifications are not reliable - they are not considered an emergency notification service
You can send an email or text message independent from user’s WiFi access
You reach a much larger group of attendees, including users who have not installed the native app at all or are only using the webapp.
You reach users that have turned off notifications for your event app
You reach attendees that have turned cellular data/WiFi off completely
Emergency and Government Alerts
Wireless emergency alerts are designed to alert people via their phones about three types of emergencies: imminent threats (including extreme or severe weather), AMBER alerts, and presidential alerts (alerts issued by the president).
Learn more on activating or deactivating these alerts on iPhone and Apple Watch https://support.apple.com/en-ie/HT202743