IZOD Indy rule 9.3(B) says that "a driver must not alter his/her racing line based upon the actions of pursuing drivers or use an abnormal racing line to inhibit or prevent passing".
So in my opinion, Helio violated this rule.
However, normally, such an infraction is ignored, unless its hugely blantant and the over-taking car is much faster.
Sure Helio blocked a little (he took the inside line to the corner so Will Power could not drive up inside of him, and then swung wide, back onto a more normal racing line once Will Power started to swing wide).
If you watch the replays' you can see the two Target cars in 3rd and 4th place are already very wide going thru this turn.
However, Helio did not swing back-and-forth across the track like some blocking maneuvers we have seen.
My feeling is that this technical rule violation should not have been used to determine the winner of the race. Some leeway in the rule should be allowed. I bet if we examined the racing lines for nearly every car in the race, we would see this rule violation nearly every time an over-taking car comes up behind a slower car if the car in front wants to maintain its track position, and the lead car is not already a lap down.
Consider the senario: Helio stays wide on the normal racing line, Will Power dives in tight at the corner and gets a slight lead. Power is fairly slow going thru the corner since he "squared it off", so he is now impeding Helio's race car. Helio has to brake more than he normally would going thru the corner so he doesn't hit the back end of Power's car.
Hasn't Will Power taken an "abnormal racing line" into the corner, which has "inhibited Helio from passing"?
So Will Power gets a drive-thru penalty and Helio wins the race!
Respectfully,
GTsail