I found the following on the perceived ruthlessness of lancers:
”In the memoirs of Waterloo, the French lancers, galloping at will over the battlefield, sending saber-armed cavalry fleeing before them, and calmly stopping to finish off the wounded without even having to dismount, appear as an image of horror. Wyndham of the Scots Grays saw the lancers pursuing British dragoons who had lost their mounts and were trying to save themselves on foot. He noted the ruthlessness of the lancers' pursuit and watched them cut their victims down. Some British cavalrymen on foot slipped in the mud and tried to ward off the lance blows with their hands but without much success.
At Waterloo Sir Ponsonby together with his adjutant, Major Reignolds made a dash to own line, and a French lancer quickly began pursuing them. While they were crossing a plowed field, Ponsonby's horse got stuck in the mud in an instant, the lancer was upon him. Ponsonby threw his saber away and surrendered. Reignolds came to his aid, but the lancer compelled both of them to dismount under the threat of his lance. At that moment, a small group of Scots Grays happened to pass a short distance away, saw the three, and galloped shouting in their direction with the idea of liberating Sir Ponsonby. "In a flash, the Frenchman killed the general and his brigade major with 2 blows of his lance, then boldly charged the oncoming dragoons striking down 3 in less than a minute. The others abandoned the combat, completely incapable of holding their own against the enemy's deadly weapon." (Barbero - "The Battle" p 163)”
http://www.napolun.com/mirror/web2.a..._Napoleon.html