You have granular control on how alerts are displayed to your visitors. They can always be shown or you can ensure that users no longer see an alert after its been displayed.
This is an alert. You will always see this alert. ×
This is an alert. You will never see this alert again after you close it. ×
This is an alert. You will never see this alert again, regardless if you close it or not. ×
This is an alert. Positioned with Target ×