Here is a minor concern of mine. Take player A and player B, who are already in a state of war:
01:00am - New Turn
03:15am - Player A moves
08:35am - Player B moves
01:00am - New Turn
...
...
...
Player A never logs in to move, pretty much forcing player B to miss a turn, else be in violation of the no double moves amendment.
A true "doublemove" is consciously going last then first. So, if you take your turn at regular intervals, then I think you're quite fair.
So, in your example.... Player B could go again w/ a free conscience at ~8 PM.