They probably had a lot to discuss and most likely were not alone.
He strolled up to them as if he was on a city street, not alone in the Colorado woods.
Besides, you're not alone.
His mother – who had been sick for weeks – was not alone in their home.
The house of Bouillon was not alone in claiming the knight of the swan as an ancestor, and the tradition probably originally belonged to the house of Cleves.