G'day David,
But that's exactly my point. _What the policy says_ is (ie 'if this happens, in this way, then this is the consequence') _all_ that achieved consensus (and therefore all the is enforceable) - anything above and beyond that is not endorsed by the community (or, in the case of decrees, not endorsed by Jimbo unless he subsequently says so) and therefore is not policy. Taking your example, if there was community consensus to extending the 3RR to 25 hours then it would be amended as such.
1) Policy is descriptive --- it *describes* what we already do, it attempts to document consensus. When we look to policy, it's because we're not sure what to do or, unfortunately rather commonly, because we want a bat to hit our opponents with and can't come up with a logical argument (see also "wikilawyering"). As a natural consequence, what policy says necessarily lags behind what we actually do --- as someone wise, or possibly Raul654, said, "do what needs to be done, and eventually someone will rewrite policy to suit". Or words to that effect. There will always be some activity on the edges where, if a bloke confines his understanding to policy (rather than to *Wikipedia*), he'll always be uncertain about what's happening.
2) The 3RR is a good example. Someone who reverts four times in 25 hours (or, indeed, 24 hours and 30 seconds) is no different from someone who reverts four times in 23 hours (or 23 hours and 59 minutes 30 seconds). They're all edit warriors, and those who happen to wait an extra minute for "their revert limit" to reset itself are doing what's called "gaming the 3RR" or, bluntly, being dicks (that's WP:DICK, which process wonks always seem to want to get rid of).
The only reason we say "three reverts in 24 hours" is because you have to draw a line, however fuzzy, somewhere. You can't accuse someone of edit warring who made three reverts in nine months, nor can you take someone who makes twelve reverts in an hour and say they're not really warring, it's just healthy boyish aggression. 3RR gives a basic definition. But at the edges ... if I make four reverts in 25 hours, I'm as bad as someone who does it in 24. Now, what if I make three reverts every day for two weeks? Is my behaviour appropriate? Am I entitled to whine about my inevitable block, because "process says I have to revert four times a day before you can block me!"? Bollocks, I am.
People are blocked all the time for gaming the 3RR. The 3RR description itself says "this is not an entitlement". 3RR is about discouraging and, in some cases, ending revert wars. I suggest unblocking someone I (or any other sensible admin) blocked for four reverts in 25 hours would be a very, very silly thing to do.