Business Insider and many other online magazines and websites limit some articles with a pay wall. User must purchase a monthly subscription to view the content.
For BI Prime, it seems like they use a 3rd party solution that manages identity and subscription but the check for logged in or authorized user happens in an API call after the content is loaded.
So disconnecting the internet right after the page loads prevents this call and the functions that handles authorization.
This is probably the worst way to do this protection.
One way to disconnect on the phone is to quickly turn on airplane mode right after you click the Prime page.
See it in action: