For one, pacemakers have to enter the race and start the race with him. You can't have pacemakers enter partway. They all have to be eligible to hit the record

For one, pacemakers have to enter the race and start the race with him. You can't have pacemakers enter partway. They all have to be eligible to hit the record too if they are capable. Per IAAF rules, pacemakers are basically just competitors that you pay to go out too fast and drop out partway. Also just not a sanctioned course, not proper testing protocol for doping, not open to other competitors, and so on. (Former USATF apprentice official, though stopped officiating once I started grad school)