Planning ahead for targets would count as time spent, ideally. Same if you are in IRC looking at the market. It would all have to be honor system really, unless it was implemented for a season of the Fiesta Server actually. Turn off the external data (like Tourney does) so people can only grab from inside the game. Timer starts when you log in and then there's an "Exit game" button on the home page that you have to click to stop the timer.