It's a split second decision, pretty difficult to stop a combination in the middle. Also as others have noted there's many examples of fighters coming back to w

It's a split second decision, pretty difficult to stop a combination in the middle. Also as others have noted there's many examples of fighters coming back to win after flash knockouts. Fighters often do stop, an example from just last week is Bahamondes vs Giagos (although this is probably not a good example of avoiding concussion). https://youtu.be/X2Z1En-eAgk?si=8lBY27afFMfv_Z90 https://youtu.be/X2Z1En-eAgk?si=8lBY27afFMfv_Z90 But there's many, many examples of fighters stopping when they know their opponent is finished, and IMO only very few examples of fighters egregiously not stopping.