Final answer:
If a tackler's helmet comes off during a play, the play is ruled dead immediately to protect the player from potential head injuries. The football organizations have safety protocols to reduce head injuries.
Step-by-step explanation:
When a tackler's helmet comes off in the act of making contact with the runner in football, the play is generally ruled dead immediately for safety reasons. Safety protocols are in place as part of the ongoing effort to reduce the risk of concussions and other head injuries among football players. Professional organizations like the NFL have developed helmet safety rating systems, and the NCAA has established protocols to limit dangerous hits. The inclination to keep playing is outweighed by the need to protect players, with an emphasis on reducing the incidence of traumatic brain injuries and increasing player safety.