I follow your reasoning on most of this, and while we don't agree, I can see where you are coming from. But the above, I have to say I think you have completely wrong. Yes, the compass on the iPhone makes it illegal because it is an APP that cannot be removed. However, assuming it COULD be, and that no other app on the phone could access the information, stating that the phone had the ability, given the correct app, to measure such information makes it illegal is not backed up by the current rules.
[quote]A multi-functional device, such as a smartphone or PDA, may be used as a distance measuring device provided it contains a distance measuring application that meets all of the above limitations (i.e., it must measure distance only).
In addition, when the distance measuring application is being used,
there must be no other
features
or applications installed on the device
that, if used
, would be in breach of the Rules, whether or not they are actually used
.[/quote]
You are, I assuming, trying to point to the bolded part above and saying that the phone's innate ability to measure direction based on GPS and Accellerometer and whatnot make it illegal even if there is no app to access the data. I would point to the second bolded part of the statement and argue that "that, if used" takes into consideration the ABILITY TO USE said app or feature. The fact that an app exists to measure wind speed and direction via the iPhone's microphone does not enter into the conversation if I don't have the app installed, just as the fact that the iPhone has an app that can display a compass if said app is not installed.
Again, moot point as the app can't be uninstalled, but we are arguing some serious nits here anyway. :)