Chaos:
Several things demonstrate that the moves within a turn are sequential rather than simultaneous. The move list shows the order of moves and vacating a square must occur prior to another piece occupying it, but I agree that these do not definitively eliminate the simultaneous move possibility. I don't care for the analogy of cars moving on a road since continuous movement doesn't reflect a turn based game. When vehicles in a particular lane start from a traffic signal turning green, in reality, they do not all start moving at the same time except in some cartoons. So that analogy demonstrates sequential better than it does simultaneous moves.
The existing state of spy identification as described in previous messages clearly demonstrates that moves within a turn are not simultaneous, but are in fact sequential.