Probably just the easiest way to put it in the computer. Guess if crewing start putting days-off on your roster it will deduct a leave day or salary. Suppose it depends on the individual situation (its day 1 of 2 days off for me today anyway) but if I was put on standby I wouldn't worry about it and just go to the pub or go out for the day if thats what you want to do. You ain't going anywhere, are you?