While I do find the comparison between the different codes fascinating (yes, I'm that kind of nerd) I'm not sure I'd totally agree with everything there.
For one thing, only the NFHS Rules allow 3 referees. The NISOA/NCAA do permit a dual referee system but only under unusual circumstances - and their rules say a single ref system "shall be used." I don't recall seeing the dual system used in an NCAA game within the last decade or so (certainly not in any higher-level/televised college games).
And I wouldn't say the NFHS Rules differ from IFAB Laws that widely, in most of the basics. There are a good number of technical differences but if anything, in recent years I'd say they've got a fair bit closer, as they seem to have made a clear effort to "mirror" changes in the IFAB Laws, for such things as dropped balls, goal kicks, kick-offs, goalkeeper movement at penalties, changes in interpretation of offside etc, etc. The main differences for me would centre around timekeeping and player equipment.
There's a bit of an underlying difference in philosophy in that that NFHS Rules are for high school kids and place a much greater emphasis on sportsmanship and player safety, for example.
I'm also not sure the NFHS (or NISOA) Rules have any implication whatever for the future of the IFAB Laws - in fact I rather doubt that many in the IFAB are even aware of what they contain.
Interesting little historical side-note - the FA did request permission to trial the dual referee system at an IFAB AGM back in 1937, but the proposal was withdrawn, for unspecified reasons.
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