No, I certainly wouldn’t suggest continual polling, but let’s say local polls every minute, then if the orientation from this minute is different to the one taken in the previous poll, then this would suggest that the phone is in a moving state… There would of course need to be some additional checks made, like ensuring the person is not already in a call, as you would expect the phone to be moving anyway, and you might want to wait two or three polls before applying the condition to confirm it is actually in a moving state…