I can speculate, I suppose. The attack at Crickhollow had raised an alarm that was spreading. They could hear the horns and bells even in Bree. Nor may the attackers at the Prancing Pony have had time to search every room before daybreak come and they would be.....weaker? And it wasn't just the Hobbits and a fat innkeeper they would be facing but a Ranger who knew how to fight back.
-- Edited by Anorlas on Wednesday 19th of August 2009 01:28:51 AM
They weren't there to slaughter everyone. It was their mission to find the Ring. Killing the peasants wouldn't have furthered that goal. Besides, thats less cattle for Sauron to drive when he's top dog. ;)
They would pretty much be wasting their time. Their main objective was to get the Ring. Killing innocent folks would only slow them down on their main objective, and it would blow away their cover of secrecy.