I would expect that they would have been greeted with a recording of Vader standing over a bound Han Solo demanding the surrender of the Rebel Fleet, if it was the case that they'd already been captured. But what was being jammed was the sensors that said whether the shield was up or down. If the Imperials wanted the Rebels to surrender they wouldn't have bothered to jam that reading, they wouldn't have jammed. They would have demanded a surrender, or simply attacked.