Please correct me anywhere I am wrong . . . as I am apt to be. Also, please correct me as I am operating under the myriad of differing pieces of information I have gathered over the years as I worked both softball and baseball, and in various parts of the country.
I am focusing on NFHS, but adjust this as needed as the concept is the same.
I am using "fourth dimension" to refer to time (not hypercubes), of course.
The central tenet of interference and obstruction is that the offender's actions directly caused an unfair disadvantage to the offended. For a multitude of reasons, our working definition of interference/obstruction has been expanded to the parameters of what could cause interference/obstruction and focused less and less on whether it actually did cause interference/obstruction.
Example: R3 rounds third and is headed home to score. As R3 is (a) 30 feet, (b) 45 feet, (c) 80 feet past third base, the catcher is waiting for the incoming throw, and is set up in the path between the runner and home plate.
In (a) and (b) the throw will beat the runner by a long shot. It is very likely the catcher's positioning had no impact on the play whatsoever.
In (c) the catcher's position is very likely going to have a negative influence and force the runner to do something the runner would not have otherwise done.
Recognizing the time element of interference would leave us with no call in (a) and (b), and a likely obstruction call in (c). However, by current standards, we have obstruction in all three.
Currently, we have few plays that allows us this discretion -- RLI, catcher's obstruction, umpire obstruction. One of the principle elements in these cases is that the offending action MUST have an impact, otherwise we ignore the circumstances.
All that said, as I read the NFHS rulebook, it seems to agree with this concept. As I have worked over the years and formats, I have been instructed otherwise. It has felt that NFHS has tried to use "over enforcement" (IMO) as a deterrent to unsafe play (think Buster Posey). If we penalize the defender for being in that position at any point, we will discourage them from being there when it can cause a problem.
USA Softball is the only rule set that I have worked where I was expressly told, "You can ignore that." Example: A runner is mildly obstructed between 2nd and 3rd base, then attempts to stretch it into a scoring play. The obstruction did NOT cause the runner to be thrown out at home plate by 10 steps. The obstruction would protect the runner between 2nd and 3rd base. If this was a close play, and the umpire judged the obstruction did have an impact on the play at home, an award would be made. Since the obstruction did NOT have an impact, the out stands.
I dunno'. Maybe I am rambling. Let me know.