If it is policy to accept late FPs then there is no "sliding" involved. And there is no "convincing" anyone. It a matter of nicely and respectfully asking the CM to check on the policy with another CM or his/her lead.
On a related note, I am genuinely curious about the non-acceptance of the late FP at Epcot's Soarin. I heard about this more frequently in 2005 and before but it seemed to have gone away in 2006.
Was your experience in the last couple years or before?[/quote]
yes, we are in WDW at least 3 times per AP

; i'd have to pull out my notes/TR; believe it was during June '07 trip
respectfully, we must agree to disagree in this matter of FPs @ WDW. For the more popular rides, during peak times; the CMs have looked @ our FPs

whether they were just checking to see if they were for the correct ride or not I cannot say
Not a matter of semantics, we were refused entrance to Soarin, that would be a "no"...by asking for another opinion/supervisor that is akin to asking for a special accommodation imo; whether you ask nicely/respectfully or not.
it just goes back to disney-speak, although the time is plainly printed on the FPs evidently, they don't follow what is printed on them all the time; depending on the CMs mood, etc
...consistency please in all things, and a level playing field for all guests, not just those who are comfortable disregarding what is plainly stated on the FPs and are either "in the know" or comfortable negotiating with a CM.
ps i'm not complaining, heck we got YOMD FP twice during our last trip

once @ MK, once @ Epcot; just trying to share my personal experience; whether it's in the majority or not.
typically, we just follow the same basic pattern of early entry (that even my youngest DS knows off by heart for all the parks) that the UG laid down years ago, works for us @ WDW. I plan on utilizing their suggestions @ DL and look forward to being able to use their FPs @ will since y'all say it's stand M.O.