I'd like to add my congratulations as well, and maybe try and answer some of the points raised.
I believe that the aim is to give the driver as much notice as possible so the distances are speed related, so at 30mph it's roughly 300 meters (15 seconds from target) more as the speed goes up, however this has limitations.
Most speed camera detectors give you 15 seconds warning to the camera site.
Limitations:
1: The target area is the total area around the car, not just the road ahead, this is why it picks up side streets and cameras on adjacent roads. Imagine the car at the centre of a big bubble, and the faster you go the bigger the bubble, any target inside the bubble when the nav asks (every 3 seconds, I think) will give the alert, regardless of where on the map it is.
2: Setting it for 50m is not enough at 30mph never mind 70mph, testing was done at 100m, 200m, 300m, and all were not really good enough for travelling at any sort of speed, which is why the speed adaptive distance is used, could this do with a tweak? possibly, this might be a good "user input" field to have, I agree.
3: I believe it is possible to have the alert turned off if travailing under a certain set limit, but as the nav system does not "know" the limit or setting of individual cameras (in the db, it only "knows" long and lat) then this would be an abitary value (eg; 29mph?), again this might be a good "user input" field to have.
Thinking out loud, If you travel in town all day then 28mph may be a good cut off, 65mph for people who use the motorway all day.
4: Stopping or slowing right down inside the target bubble will make the nav re-emit the alert (this is because the car thinks you are setting off again).
5: I think nomad was saying that it may be possible to have the POI alert user turn off/on in the cars menu system, but that it may be problematic to implement, we will have to see if nomad can do it, (he really is very clever, lol).
Things I'd like, but I don't think are possible,
1: Only the front of the car monitored (@90Deg (45 each side)) or only the road ahead (but, see point 1).
2: No alerts when below the set camera speed (but see point 3 above).
3: More than one POI on screen with different alerts.
4: User definable perimeters for the navboot hack.
5: Only 1 alert (ever) per target (regardless of slowing or stopping etc).
We will need to wait and see I think, but we can ask
Nomad: please correct any mistakes I've made or any wrong assumptions. (all mistakes are mine alone)