UAL global flights have contract pay extension language. Nobody extends domestic since there is no benefit to it. Like the other guy said, off to the hotel with no phone calls or explaining to do.

A :30 minute extension gets you 2 hrs add pay.

The next 1:30 hr extension gets you a total of 5 hours add pay.

When our BOM flights leave EWR, usually less than an hour of delay time until your getting extension add pay. Very senior trip for that reason alone.