As an aside, I believe Preston Brooks had the common decency to commit suicide, didn't he? I know he died less than a year after he maimed Senator Sumner and I think I read somewhere that he killed himself. Maybe one of you oracles of the pantheon of sothron 'heroes' knows?
I don't believe Butler had any knowledge of it. He wasn't even on the senate floor when Sumner stood there mocking his stroke-induced disabilities. Brooks simply felt that his family's honor had been insulted by an act that, with any other individual save a few from the scum of the Sumner crowd, would have resulted in a duel. But historic codes of dueling, which trace back to the trials by combat of medeival Europe, say the event is reserved for satisfying honor among peers. A gentleman duels with a gentleman, but a gentleman does not duel with a sloth, vagrant, or low life of society. For such situations, a gentleman satisfied honor by caning the vagrant. Brooks considered Sumner to be such a vagrant on reasonably good grounds (heck, half the Republican Party hated Sumner and considered him a nuisance!). So, after consulting the advice of dueling experts, Brooks, who was no stranger to the duel, concluded that Sumner was to be appropriately dealt with by a caning.
Second, make sure the intended victim is unarmed and unprotected.
As opposed to the norther way of doing things, which includes mocking somebody else's physical handicaps when they aren't even present to defend themselves.
Third, make sure you don't do it alone but instead bring an accomplice along to prevent anyone from coming to the unarmed man's aid while you batter him with your club.
Actually, Brooks' accomplice was an expert on dueling and other actions of recourse for honor. Tradition says one brings such a person to events of this nature, as Brooks had done previously when he dueled amongst peers.
Fourth, make sure your accomplice is armed in a similar manner.
The double to a duel comes with a pistol as well.