The Blood Exchange Duel had become an awkward tradition in the history of the Great Ratholos Empire. Although it was a flawed law, the previous emperors didn't remove it, perhaps due to their pride.
As such, the Blood Exchange Duel had an awkward period where it existed, but no one dared to use it.
It was only during the last fifty years that the Blood Exchange Duel had deviated from its original purpose and became standardized for betting duels instead. Although it was still a duel of life or death, it was not as serious as when it was first introduced.
After all, fists and swords had no eyes.
No one could guarantee an accident wouldn't happen during an intense spar, especially with lucrative wagers involved. Warriors would go all-out to defeat their opponents and claim their prizes. As such, accidental deaths were unavoidable.