Mustrum_Ridcully
Legend
Everything you say here is pretty reasonable. However, the way I see it, the inter-player social contract is not a replacement for sound game design. Rather, it's another layer. Bother have their place. There will always be messy rules, but there are degrees of acceptability.
And this one is pretty acceptable to me or hong, apparently. And also the designers, I suspect. "You fly n squares" means you fly that distance. You don't get a flight speed. You find it not described clearly enough.
Maybe that means the PHB 3 glossary or the DMG 2 will have a note on that. But in the end, who will that really help? Only those that read the note and don't forget it when its content ever comes up.
That's why player and DM being able to talk each other about unclear rules is so important. If unclear, the DM makes a ruling on the spot.
Or he doesn't, and instead spends a time to consult various rulebooks on the issue of "flying" and figure out what the RAW is.