Has anyone else seen this?

[Mike Simonds]

This picture answered a lot of doubt in my mind. The line judge was correctly watching his receiver in the middle of the field. Mr. Porter was the correct official to make the call. The cornerback does not appear to be playing the ball. He appears to be impeding the receiver's ability to move towards the ball. The receiver is looking back at the ball as he is entering the endzone. Also, note the cornerback's hand and arm near the receiver's mid-section. Obviously the DB is playing the man and not the ball. Good call!