A few points to consider:
1) Rule 160.2 (Track Measurements) states:
The measurement shall be taken 0.30m outward from the kerb or, where no kerb exists on a bend (or the diversion from the track for the steeplechase water jump), 0.20m from the line marking the inside of the track.
In other words, to run a true 400m lap you have to perfectly maintain a distance, depending on the presence of a curb, seven to eleven inches away from the line marking the inside of the track. Any lap ran where the runner stays, say, two inches from the line marking the inside of the track –and this describes a lot of laps-- is already shortening the distance. Yet that’s technicality allowed by the rule. Perfectly acceptable.
So my question: where then do you draw the line? At what point does a runner violate the rule and is considered to have gained a material advantage when running a bend?
2) Is the presence of a curb a deterrent from stepping on the line marking the inside of the track? There’s a lot of mayhem coming out of the water. Is the presence of a curb a trip hazard? Because if you step on the curb that’s directly over the line marking the inside of the track on a bend, it’s loud, you may fall and technically you’re still violating of Rule 160.2.
3) Track could benefit from more of an “out of bounds†mindset. In basketball, football and tennis the playing field is defined by clear, accepted boundaries. No one argues or files a protest if Steph Curry’s heal touches the out of bounds line even so little as a quarter of an inch. Is a quarter of an inch really a material advantage? Doesn’t matter. He’s out of bounds.