When admin key is used access a restricted page from REST API, it does not send the email to the page owner. It also does not create an entry in the Confluence audit logs about the page access. Both these features are available when the page is accessed from UI.

Steps to replicate:

1. Enable the admin key (Doc: https://developer.atlassian.com/cloud/confluence/rest/v2/api-group-admin-key/#api-group-admin-key)
2. Get the page content using: 

   https://{your_domain}/wiki/api/v2/pages/{pageID}?body-format=storage

   Keep the header Atl-Confluence-With-Admin-Key: true

Sample cURL:

curl --location 'https://{your_domain}/wiki/api/v2/pages/{pageID}?body-format=storage' \
--header 'Accept: application/json' \
--header 'Atl-Confluence-With-Admin-Key: true' \
--header 'Authorization: Basic <key>' 

         3. Check the Confluence audit logs and email inbox.

The logs are visible under admin audit logs (admin.atlassian.com > Insights > Audit logs)