Or if Ney had sent forward some light cavalry to reconnoiter the crossroads at Quatre Bras at some point in the morning, he'd have seen that Wellington was not

Or if Ney had sent forward some light cavalry to reconnoiter the crossroads at Quatre Bras at some point in the morning, he'd have seen that Wellington was not waiting there on the reverse slope. Had he seized the crossroads, he could've totally changed the circumstances that led to the battle at Waterloo.